Eggs and egg cases 


When a creature has emerged from its egg, the remains of the egg case often gets washed up onto our beaches.


Some of these egg cases may even have embryonic creatures still inside. If you can see a tiny shark or a tiny ray moving in cases like the ones on the left, take them to your local aquarium who may be very interested in seeing if they can be brought to the point of hatching,


Mermaid's purses

- ray egg cases


I assume that mermaids are now swiping their debit cards like the rest of us instead of carrying around bulky purses but, back in the day, it was thought they would use the egg cases of rays/skates for their coins. And presumably, after they'd spent up, they would simply throw their purses away which is why we find so many of them on our strandlines.

Spotted ray


This is the smallest of the ray egg cases found commonly in the UK.

Undulate ray


A relatively 'stocky' egg case with short tendrils.


Thornback ray


This egg cases has distinctive 'frilled' sides.

Cuckoo ray


The cuckoo ray is a deeper water species and so its egg cases wash up relatively rarely. It has long, slightly curled tendrils.



Shark eggs

Small spotted cat shark

Confusingly, this shark is also known as a lesser-spotted dogfish. And, when it is served up in a restaurant, it is called a rock salmon, although it is certainly not a salmon. It is the smallest of all the egg cases we tend to find. A dogfish can be seen here.


Sometimes, a bunch of cat shark egg cases will be washed up with their curly tendrils all tangled up together.



The egg case of a small-spotted catshark and that of a nursehound (described below) can look very similar with their curly tendrils and narrow shape. However, the catshark egg case is much smaller than that of the nursehoud.


The twho photos below have the same hand, the same beach, but the top one is the small catshark, and the one below is the large nursehound.





This is generally a larger egg case - it still belongs to a type of shark but is three times the size of the small spotted catshark case (above), for example. It is often around 10-15 centimetres long (see above for a size comparison with the catshark eggcase)..


When I found the nursehound egg case below, the tiny little fish slipped out of it. It didn;t look like it had been dead for long. I wonder what killed it when it was so nearly ready to emerge?


Whelk eggs


These balls of papery, veined, little eggs are whelk eggs, large, slow-moving sea snails that live in our waters. They have sometimes more orangey or beige than white depending on how old they are. By the time we see them on the strandline, the tiny snails have usually long-sinced hatched. Lee captured the whelk below in the act of laying her eggs. Thanks for the photo Lee!

Sting Winkle eggs


These are small, flat papery upside-down heart-shaped eggs which, in number, look a bit like an eaten corn on the cob. On the left, they are stuck fast to razor clam shells although they have long since hatched. The sting winkle can be seen here.

Periwinkle eggs


Periwinkle eggs are often found attached to wrack seaweed.





Netted Dog Whelk eggs


These can seemingly be laid on anything -  like the Necklace Shell Skirt below.

Sea slug eggs / nudibranch eggs


As with sea slugs themselves, sea slug eggs come in all shapes and sizes. Have a look at this page for more.

Egg skirt of a necklace shell


The necklace shell (also known as a moon snail) (pictured below), carries its eggs on a 'skirt' which is stuck all around the outside of the shell. The skirt itself, once it is picked up on the strandline, is like a thin dried leather material, generally still holding the shape it would have had when it encircled the parent's shell.


The photo on the right shows how the snail makes itself a skirt which is wrapped around the outside of the shell. The eggs are protected underneath it.

Source:Jarek TuszyƄski,Wikimedia Commons. The licence.

Sea Hare eggs


Like colourful strings of jelly spaghetti, sea hare eggs can often be found amongst the seaweed. For more, visit our page on sea hares.

Green Leaf Worm eggs


A soft green blob of eggs about the size of a penny. More on green leaf worms here.


Lumpfish roe


This lump of tiny fish eggs (known as roe) is from a lumpfish. It looks just like a clump of old, dried up tapioca pudding. That reminds me - what's for tea?

Sand Goby eggs


The male goby stays with the eggs, which the female often lays inside a shels, unti they hatch.

Blenny eggs


These tiny eggs - less than 1mm across - were on the underside of a flat stone exposed on the sand at low tide.
On the right hand side of the stone there is a small chiton which serves a little as scale.

Squid eggs


Squid eggs can be washed up in masses looking a bit like a mop of soft stringy straws. The female does her best to lay her eggs (which she does thousands at a time) in safe places but she doesn't stay with them and as they can take two months to hatch, they can be washed away like this. For more on squids, have a look at our page on cephalopods.

Cuttlefish eggs


The female cuttlefish lays hundreds of eggs in the spring but dies very soon afterwards. The eggs can hatch anything up to two months after they have been laid depending, it would seem, on factors such as sea temperature.


For more on cuttlefish, have a look at our page on cephalopods.