QUEEN ANGELFISH: COLOURFUL CORAL ROYALTY – BAHAMAS REEF FISH (13)
One of the earliest posts in the Bahamas Reef Fish series was about Queen Angelfish Holacanthus ciliaris, and you can see it HERE. I make no apology for returning with some more recent photos from Melinda Riger – these fish deserve plenty of attention for their wonderful bright presence that stands out even amongst the colourful corals of the reef.
UNDERWATER BAHAMAS: REEF GARDENS (3)
We are back in the realm of ‘animal, vegetable or mineral?’. Dive down a few feet – inches, even – to the reef, and… is this thing waving about here a plant or a creature? And is that colourful lump over there a bit of inanimate rock or a living thing?
1. FEATHER DUSTERS
2. BASKET STARS Creatures in the same family group as brittle stars. Take a close look at the remarkable transformation in the two photographs. The top image is taken in daylight. The star is off duty and enjoying some downtime. However the second image is the same view at night, with the star fully open and waiting to harvest whatever micro-morsels come its way. The star has truly ‘come out at night’.
3. CORKY SEA FINGER Another form of gorgonian coral, sometimes known as dead man’s fingers… **
4. GOLDEN ZOANTHIDS Coral forms living on a Green Rope Sponge. Some zoanthids contain a deadly poisin called palytoxin, which may do unspeakable things to your heart. Like stop it. Luckily, none so unpleasant live in the Bahamas (or so the Bahamian Tourist Board would no doubt wish me to make clear).
REEF GARDENS 1 Anemones, Basket Stars & Christmas Trees
REEF GARDENS 2 (Corals)
Image credits, with thanks: Melinda Riger @ Grand Bahama Scuba
** I knew this image reminded me of something… or someone. And (superannuated British rockers out there), is it not exactly like the hairdo of one of the guys in Mott the Hoople, a band lifted from relative obscurity to fame by being gifted a song by David Bowie? Guitarist. Ian Hunter. Take a look at him now… and just imagine then
TAKING A CLOSER LOOK: ROCK POOLS ON ABACO
Here’s a promising-looking rocky outcrop a short distance south of Crossing Rocks. The action of the sea over centuries has eroded and pitted it – ideal for the formation of pools in which marine life can thrive.
At the bottom of these photos, you can see that a zebra-marked nerite is quite happy to share a hole with an urchin. There are two brownish accretions on or in the rock. My tentative suggestion is that these are the shells of some sort of worm, perhaps petaloconchus.
UPDATE Rick Guest helpfully comments “Yes, it’s quite the invertebrate hotel mostly due to the urchin’s talent for scouring out protective “rooms”. Of interest is the Magpie shell (Livona pica) in frames 4 and 5. The rather ubiquitous Livona’s very thick shell, (Up to 5″ diameter) and ability to withstand most attempts at removal by predators, including Homo sapiens, assures their continued presence on littoral shore lines. They are edible, but not particular tasty to my palet. All these “Condo” residents “party” at night and will even leave the rock in search of food and perhaps romance, so a flash pic of the condo at night would be an interesting contrast to a daylight shot”.
In a snug little cave (top right) just above the water-level of the pool is a primitive-looking chiton, a species that has been around for millions of years. Below, there’s a clearer image of one from a different pool. These creatures always remind me of school projects on prehistoric trilobites.
The rough rocky surfaces close to the pool are covered in shells. The stripey nerites are small, the grey shells really are miniature. They are mostly littorines/ periwinkles and perhaps ceriths, I think.
Close-up views of nerites showing their distinctive markings and spirals
STICKING THEIR NECKS OUT: BAHAMAS REEF FISH (11)
The coral reefs of the Bahamas provide a home for a myriad of subaquatic creatures and plants. Not necessarily a safe one, though. Some species prefer to remain largely hidden to reduce the chances of becoming part of the lengthy reef food chain. Rocks, of course, can offer some security, but also the sandy bottom. Even brain coral can provide some protection…
SMALL SHELLS FROM CASUARINA, ABACO
The shell species below (also in the header picture) is an olive. It turns out to have potential to star in a small maritime horror movie. Capt Rick Guest, who kindly keeps an eye on my shell and other sea-related posts, writes “Interestingly, the previous occupant of the first and last shell pictured here is a major predator of the other Bivalve shells shown. The Olive shell hides under the sand by day, then emerges at night to feast upon small Bivalves, and any other available prey. One can often trace the nocturnal trails of this Olive shell in sand on calm mornings with mask and snorkel, and thrust a hand under a trails end for this fellow. When kept in an aquarium, they will consume any meat offered.” “Olive and Let Die”, maybe?
CONCH SHELLS & CONCHUPISCENCE ON ABACO
Most conchs encountered in daily life are lying peacefully on the beach; or are artfully displayed; or are found in conch heaps (often in the vicinity of restaurants) like the ones below at Sandy Point.
It’s easy to forget that these shells are more than just a garden adornment, or pretty containers for a ubiquitous Caribbean food. Under the sea, and not very far at that, are living creatures going about their daily lives.
And that includes reproducing. This sounds as if it might be a cumbersome process, but (like porcupines) they seem to manage. Here is a pair preparing to mate. The male behind is presumably about to… well never mind. I’ve never seen the process, so it’s a case of using imagination. Or just accepting that, whatever it is that they do, it works. [I haven't located a video online - I'll post one if I do]
You’ll find some more about Conchs in a previous post HERE, including 12 Unputdownable Conch Facts, notes on conservation matters and… a photo of Honeychile Rider, arguably the most famous conch-carrier ever. Oh, she was fictional, you say? But I always though she… How very disappointing.
And if you want to know how to clean a conch, a dude will show you in a video on this page HERE
Finally, check out the very informative website COMMUNITY CONCH, a charitable conservation organisation
Photo credits: Melinda, Clare, RH
UNDERWATER REEF GARDENS IN THE BAHAMAS (2): CORALS
This is part 2 of a series that started out HERE with a selection of anemones, basket stars and Christmas tree worms. The images below show a wide variety of corals. In among them are also sponges and anemones. These photos are evidence of a healthy reef environment in the waters of the northern Bahamas. Abaco’s coral reef is the third largest barrier reef in the world (yes, I hear you – the Great Barrier… And the second is???), providing wonderful and accessible diving / snorkelling opportunities. However, monitoring shows that the incidence of coral bleaching and disease is increasing in the Bahamas, as elsewhere in the world. It’s a sobering thought that your grandchildren may never swim in an environment with any of the living corals shown below…
Image Credits: ©Melinda Riger @ Grand Bahama Scuba
UNDERWATER REEF GARDENS IN THE BAHAMAS (1)
Animal, vegetable or mineral? If you dive down and take a close look at a reef, you’ll soon find that it isn’t easy to tell what is what… That ‘plant’ is a magic worm; this ‘creature’ is a tentacled plant…
Thanks to scuba photographer extraordinaire Melinda Riger of Grand Bahama Scuba; & wiki-minipics
SHORE THINGS: BEACHCOMBING ON A PRISTINE ABACO BEACH
The Abaco bay known as Rolling Harbour is a 3/4 mile curve of white sand beach, protected by an off-shore reef. The beach is pristine. Or it would be but for two factors. One is the seaweed that arrives when the wind is from the east – natural and biodegradable detritus. It provides food and camouflage for many species of shorebird – plover and sandpipers of all varieties from large to least. The second – far less easily dealt with – is the inevitable plastic junk washed up on every tide. This has to be collected up and ‘binned’, a never-ending cycle of plastic trash disposal. Except for the ATLAS V SPACE-ROCKET FAIRING found on the beach, that came from the Mars ‘Curiosity’ launch.
We kept is as a… curiosity, until it was eventually removed by the men in black…
I’d intended to have a ‘plastic beach trash’, Atlantic-gyre-rage rant, with angry / sad photos to match. Instead, I decided to illustrate a more positive side to beach life – things you may discover when you take a closer look at the sand under your feet. Like the coconut above. Many of these photos were taken by our friend Clare Latimer (to whom thanks for use permission); some by me.
Thanks to Capt Rick Guest, who has contributed an interesting comment regarding the sea biscuit with a hole in it. He writes “the (Meoma) Sea Biscuit w/ the hole in it was dined upon by a Helmet Conch. The Cassis madagascariensis, or C.tuberosa drills the hole w/ its conveyer-belt-like radula teeth w/ some help from its acidic, saliva. Probably 98% of all symetrical holes in marine invertebrates are of this nature. Murex, Naticas, Helmets, and many Cephalapods (via a Stylet), are the usual B&E suspects. The Cone shells utilize a modified radula in the form of a harpoon which is attached to a venom tube.” For more on the vicious cone shell, and other creatures to avoid, click HERE
DRIFTWOOD. IT’S LIKE… OH, USE YOUR IMAGINATIONA WILSON’S PLOVER NESTHORSESHOE CRAB (LIMULUS)A SCULPTURE? AN EMBRYONIC SHELTER? LARGE BIRD FOOTPRINTSMORE BIRD PRINTS AND CRAB TRACKS CRABUS CUTICUSCONCH SHELLS & OTHER BEACH TREASURESCRAB HOLE & TRACKSSOME IDIOT’S LEFT HIS… OH! IT’S MINE
‘BEAUTY & THE BEACH’: A CLOSE LOOK AT SOME ABACO SHELLS
UGLY BUG BALL…
All shells – & the spider crab carapace – collected from the beach at Casuarina
“ROCK & ROLLING WAVES”: ROCK EROSION ON ABACO
On 26th October 2012, the ‘roof’ of the geological feature at the southern tip of Abaco known for centuries as Hole-in-the-Wall was blasted apart by Hurricane Sandy. The combination of huge waves and powerful winds proved too much for a structure that had existed since the last ice age. I posted in detail about this event last year HERE so now I will concentrate on some geological aspects.
The photo below shows the Hole a year or so before its destruction. At the left-hand end of the bridge there is a paler area underneath where limestone rock had recently fallen into the sea, suggesting an underlying instability. At close quarters there were plenty of cracks in the apparently solid structure. (I’ve no idea why I didn’t straighten the image. Let’s say… Artistic Perspective)
This photo was taken a few days after the collapse, the first to be published of the new view. The clean white rock at either end of the ex-bridge is clearly visible. The section on the left became a new islet at the southern extremity Abaco, separated from the mainland for the first time in history. I proposed various names for it (not all serious) – Sandy Cay (or Isle) was the clear, indeed obvious, winner…
This close-up of the south side of the bridge shows the detail of the rock fragmentation. Tara’s photographs are (as far as I know) the very first of the new gap and of Abaco’s new islet, predating John Haestad’s by a day.
◊ ◊ ◊ ◊ ◊ ◊ ◊ ◊ ◊ ◊ ◊
We recently went to a beach near Crossing Rocks that we had never explored before (plenty of interest there for later posts). We were struck by the fragmented and pitted nature of the limestone rocks on the shoreline. We noticed some pale exposed rock surfaces, similar to those at Hole-in-the-Wall. We watched the incoming waves scouring and undercutting the rocks, leaving overhangs (see video below). Erosion is increased by the double action of the waves. The immediate area hinted that there may even have been a very small Hole at one time. On the day we were there, the sea was gentle. It’s easy to imagine how the hugely destructive force of the wind and crashing waves resulting from hurricanes such as Sandy can eventually shatter solid rock that has been gradually eroded and destabilised over centuries by wave action.
Photo credits as shown / RH. You have Mrs RH to thank for a shorter (50 secs) video than the one I originally made (75 secs). Now I’ve redone the thing, I agree – one wave does look very like the next…
ADDENDUM Just remembered that I took an aerial photo of HitW from the plane the other day. It’s a phone photo through BahamasAir window glass, and I’ve had to tweak it a bit. It shows the relevant area…all the blurry dark stuff is part the pine forest of the National Park
ADDENDUM 2 In response to a comment about the power of hurricanes, here is an image I have posted previously of a large rock some way out from the Delphi beach. Before Hurricane Irene in 2011, it was a solid rectangular slab. This is what it was like after Irene had moved on northwards
SPOTTED DRUM FISH Equetus punctatus BAHAMAS REEF FISH (1)
This post is the first of a planned series on Bahamian reef fish. Those who follow this blog (I thank you both) may recall with horror (or worse, pity) my own efforts with reef fish, using a tiny cellphone-sized video camera. Misty stills culled from video footage. Enthusiastically wobbly movies as I struggle to swim and breathe simultaneously in an alien element. I am more underwater CLOUSEAU than COUSTEAU. However, thanks to Melinda Riger, who with husband Fred runs GRAND BAHAMA SCUBA, I have kind permission to borrow and display images from her stock of wonderful reef fish photographs.
The spotted drum fish (or Jack-knife fish) belongs to a large worldwide family, the Sciaenidae. Besides other drum varieties, the family includes ‘croakers’. These species are all named for the repetitive throbbing or drumming sounds they make. This involves the fish beating its abdominal muscles against its swim bladder. If I find out the reason for this (Species communication? Food call? Alarm? Warning? A piscine ‘advance’? Happiness?) I will add it here in due course. Here an example of an atlantic croaker from the excellent DOSITS site (Discovery of Sounds in the Sea)
The spotted drum is one of the few fish of the species to inhabit coral reefs – most are bottom-dwellers (often in estuaries), avoiding clear water. These fish tend to be nocturnal feeders, feeding on small crabs, shrimp and small invertebrates. As far as I can make out they are solely (or primarily) carnivore, and do not graze on algae of other reef plant life.
The photos above are of adult spotted drums. The ones below are of juveniles, and show the remarkable growth-pattern of these fish, from the fragile slender creature in the top image, through the intermediate phase of the one below it (with the amazing brain coral), to the striking adult versions above. People like to keep these pretty fish in aquariums; fine, I’m sure there are plenty to go round, but these ones look pretty happy to me in their natural reef environment…
Juvenile drum fish (school-age)
Finally, I’ve just come across this short video from a “Florida Aquarium”, showing how these fish swim. It rather looks as though it has been fin-clipped for some reason… or just damaged, maybe
KING HELMET SHELLS (Cassis tuberosa) FROM THE DELPHI COLLECTION
It’s time to look at another shell from Delphi. The club has glass jars displaying small shells in the Great Room. Larger shells like the ones below are displayed on shelves. The King Helmet is the largest of the helmet shells of the family Cassidae. They are found in the Western Atlantic from North Carolina through the Caribbean and the gulf of Mexico down to Brazil. They tend to bury themselves during the day, becoming active and feeding at night. In humans this behaviour is found mainly in students and in those involved in the music business and similar louche occupations.
King Helmets prey mainly on sea urchins and other echinoderms, using their foot to grip their meal. The dining arrangements are somewhat protracted. The snail makes a hole in the urchin through the combined action of a glandular secretion which is rich in sulphuric acid, while using its RADULA to rasp and dig through the shell to get at the trapped occupant, which it gradually consumes… That’s enough about that.
FLAMINGO TONGUE SNAILS & SHELLS: COLOURFUL GASTROPODS OF THE CARIBBEAN
The FLAMINGO TONGUE SNAIL Cyphoma gibbosum is a small sea snail (marine gastropod mollusc), related to cowries. The live animal is brightly coloured and strikingly patterned, but that colour is only in the ‘live’ parts – the shell itself is pale and characterised by a thick ridge round the middle. These snails live in the tropical waters of the Caribbean and wider western Atlantic. Whether alive or dead, they are easy to identify.
This snail on the left (thanks, Wiki) is snacking on a coral stem, leaving a feeding track behind it. The structural shell ridge is clearly visible beneath the distinctively marked live tissue.
The flamingo tongue feeds by browsing on soft corals. Adult females attach eggs to coral which they have recently fed upon. About 10 days later, the larvae hatch. They eventually settle onto other gorgonian corals such as Sea Fans. Juveniles tend to live on the underside of coral branches, while adults are far more visible and mobile. Where the snail leaves a feeding scar, the corals can regrow the polyps, and therefore predation by C. gibbosum is generally not harmful to the coral.
The principal purpose of the mantle of tissue over the shell is as the creature’s breathing apparatus. The tissue absorbs oxygen and releases carbon dioxide. As I have seen it described (unkindly?) “it’s basically their lungs, stretched out over their rather boring-looking shell”.
This species was once common but is becoming rarer. One significant threat comes from snorkelers and divers who mistakenly think that the colour is the shell of the animal, collect up a whole bunch, and in due course are left with… (see photos below)
These photos are of flamingo tongue shells from the Delphi Club Collection. Until I read the ‘boring-looking shell’ comment, I thought everyone thought they were rather lovely… you decide!
Finally, a couple of videos. The first is rather charmingly titled ‘FLAMINGO TONGUES DOING…. SOMETHING’. Any (printable but amusing) suggestions via the Comment box are welcome (Hi Trish!). The second punchily summarises this post. Maybe that’s all that was needed!
ABACO SHELLS: 3 MORE FROM THE DELPHI CLUB COLLECTION
I have recently featured some of the shells from the collection amassed at Delphi – see SHELLS 1 and SHELLS 2. They are kept in vases or bowls for display and examination. They may not all come from the immediate vicinity, but they are all, for sure, from South Abaco. It’s time for some more.
PINK TRIVIA SHELL
LETTERED OLIVE SHELL
For further details about Spirula(e), please see the comment box where Capt Rick Guest gives a lot of fascinating info about them and related marine cast-offs. You’ll also find out which are the real prize ones to look out for…
CARIBBEAN CORAL REEFS FACE COLLAPSE
Caribbean coral reefs are in danger of disappearing, depriving the world of one of its most beautiful and productive ecosystems
Guardian: Monday 10 September 2012 03.00 BST
• INTERACTIVE GUIDE: CORAL REEFS AROUND THE WORLD
• WHAT DOES A CORAL REEF SOUND LIKE?
Caribbean coral reefs – which make up one of the world’s most colourful, vivid and productive ecosystems – are on the verge of collapse, with less than 10% of the reef area showing live coral cover.
With so little growth left, the reefs are in danger of utter devastation unless urgent action is taken, conservationists warned. They said the drastic loss was the result of severe environmental problems, including over exploitation, pollution from agricultural run-off and other sources, and climate change.
The decline of the reefs has been rapid: in the 1970s, more than 50% showed live coral cover, compared with 8% in the newly completed survey. The scientists who carried it out warned there was no sign of the rate of coral death slowing.
Coral reefs are a particularly valuable part of the marine ecosystem because they act as nurseries for younger fish, providing food sources and protection from predators until the fish have grown large enough to fend better for themselves. They are also a source of revenue from tourism and leisure.
Carl Gustaf Lundin, director of the global marine and polar programme at the International Union for Conservation of Nature (IUCN), which published the research, said: “The major causes of coral decline are well known and include overfishing, pollution, disease and bleaching caused by rising temperatures resulting from the burning of fossil fuels. Looking forward, there is an urgent need to immediately and drastically reduce all human impacts [in the area] if coral reefs and the vitally important fisheries that depend on them are to survive in the decades to come.”
Warnings over the poor state of the world’s coral reefs have become more frequent in the past decades as pollution, increasing pressure on fish stocks, and the effects of global warming on the marine environment – in the form of higher sea temperatures and slightly elevated levels of acidity in the ocean – have taken their toll.
Last year, scientists estimated that 75% of the Caribbean’s coral reefs were in danger, along with 95% of those in south-east Asia. That research, from the World Resources Institute, predicted that by 2050 virtually all of the world’s coral reefs would be in danger.
This decline is likely to have severe impacts on coastal villages, particularly in developing countries, where many people depend on the reefs for fishing and tourism. Globally, about 275 million people live within 19 miles of a reef.
IUCN, which is holding its quadrennial World Conservation Congress on Jeju island in South Korea this week, said swift action was vital. The organisation called for catch quotas to limit fishing, more marine-protected areas where fishing would be banned, and measures that would halt the run-off of fertilisers from farmland around the coast. To save reefs around the world, moves to stave off global warming would also be needed, the group said.
On a few of the more remote Caribbean reefs, the situation is less dire. In the Netherlands Antilles, Cayman Islands and a few other places, the die-off has been slower, with up to 30% coverage of live coral still remaining. The scientists noted that these reefs were in areas less exposed to human impact from fishing and pollution, as well as to natural disasters such as hurricanes.
The report – compiled by 36 scientists from 18 countries – was the work of the IUCN-coordinated Global Coral Reef Monitoring Network.
GLIMPSES OF LIFE ALONG A CORAL REEF by F. H. HERRICK
This post is aimed at those with a particular interest in the flora and fauna – especially avifauna – of Abaco and its Cays. It is a naturalist’s account from 1886 of an expedition to Abaco, interspersed with a few line drawings. It’s an easy read if you are interested in Abaco, its history, and the state of natural life on the islands 125 years ago. Those who have come to this site for the photos and / or even the occasional jest are warned to expect neither. However, to tempt waverers I’ll highlight below (by way of a quiz) some intriguing aspects of the 9-page article. I have had to edit it to correct the many ‘literals’ in the open-source material; however the c19 spellings are retained. I’ve also added coloured subject-matter codes as follows: PLACE NAMES; BIRDS; PLANTS; FISH; CREATURES
In 1886, Herrick visited Abaco with a party of naturalists. This trip predated by 3 years the publication of Charles Cory’s groundbreaking ‘Birds of the West Indies‘. There would have been scant readily-available published material about the natural history of the Bahamas, let alone of Abaco itself. Herrick and a friend left the main party and went on their own wider explorations of Abaco with two local guides. Herrick recorded their findings, which were subsequently published in ‘Popular Science Monthly‘ in 1888. In Herrick’s wide-ranging account of the adventure you will find the answers to the following 15 questions. If any one of them whets your appetite to read this historic account, press the link below the quiz!
- What fruit might you have found growing in fields on Abaco in 1886?
- What was the local name for the perforated rock at Hole-in-the-Wall?
- What is an “egg-bird”?
- What was causing “the gradual extermination” of flamingos?
- What were “shanks” and “strikers”?
- To what human use were Wilson’s Terns put?
- How many eggs does a tropic-bird lay?
- What law prevented the shooting of tropic-birds, and indeed any other bird, by naturalists?
- What sort of creature is a “sennet”?
- Which was rated the better for eating – grouper or ‘barracouta’ (sic)?
- Who or what is or are “grains”?
- What common creature had a burning touch like a sharp needle?
- What bird was reckoned to have the call ‘loarhle-ee’ ?
- What – or indeed who – was described as a ”pilepedick”?
- What creature laid 139 eggs?
TULIP SHELLS & SUNRISE TELLINS: MORE SHELL TREASURES FROM ABACO
Here are two contrasting shells from the Delphi Club collection that has been haphazardly accumulated over the last 3 years or so. The first post in this shell series was about SEA URCHINS & SEA BISCUITS
TULIP SHELLS Fasciolaria tulipa
The term ‘Tulip snail’ includes 3 related species of sub-tropical gastropod worldwide, of the genus Fasciolaria. They are medium-sized predatory molluscs that breed throughout the year in warm waters. Their reproductive lives deserve some attention, if they will pardon the intrusion.
Research by the Smithsonian Marine Station Fl. reveals that the male’s penis is to be found on the right side of its body, directly behind its head… When they mate the (larger) female stays in an upright position on the sand while the male ‘flips over’ to align the apertures of both shells, before inserting the penis into the female (RH comment: the research is not specific about precisely where the female keeps her own genitals). Once joined, snail pairs may remain locked together for up to 2 hours, even when being watched by researchers. They have plenty of stamina: mating may occur several times in one season, and individual tulip snails have been observed to mate up to 3 times in a single week. Respect!
SUNRISE TELLINS Tellina Radiata
I included these pretty shells, with their striking pink radials, in an earlier post BEACHCOMBING BIVALVES The ones shown here are larger specimens. The hinges (muscles) are very delicate, and in these shells the two halves of the shells have separated. STs are not uncommon, but these are the largest I have come across (I realised after I had taken the photos that I should have used a coin for comparison…). They grow up to about 7 cms, and these ones were that length, or very nearly so.
I can’t assist with their sex lives I’m afraid, which may well be completely conventional, dull even. However, as I discovered when I previously researched these shells, “in most countries it is illegal to bring back these shells from holidays”. To which I can only repeat my comment: Whoops!
SEA URCHINS & SEA BISCUITS – BEACHCOMBING TREASURES ON ABACO
It’s time we had some more shells and other beach treasures on these pages. In the absence of star Abaco beachcomber and blog-contributor KASIA I have taken a closer look at the Delphi Club collection. This has been casually accumulated by the Club, its members and guests during the past 3 years whenever a good specimen has been encountered, and is displayed in the Great Room. The first items to catch my eye were the ECHINODERMS, a family that includes sea urchins, sand dollars, sea biscuits and star fish. Their sun-bleached tests are often found, though in my limited experience the larger they are, the rarer. The link above is to the Wiki-blurb, which has the unpromisingly daunting heading “This article may be too technical for most readers to understand…”. Now there’s a challenge!
First up is a very large SEA URCHIN, a thing of great delicacy and fragility that weighs next to nothing. I have never seen a bigger one. Looking at the fine detail, it is hard to believe that such perfection of symmetry and intricacy can exist in a creature so very painful to tread on.
SEA BISCUITS have similar five-way symmetry to their first cousins SAND DOLLARS but are generally pebble-shaped rather than disc-shaped. I have included 2 close-ups to show the fine details of the pattern – almost like lace-work
This SEA BISCUIT is a different type, with the 5 radials reaching right round it. For some reason it only has 4 and not 5 small holes (as one might expect) at the centre. Unlike SAND DOLLARS they tend to be more oblong than round.