Egg Case

Long-time readers may know that my most popular blog post ever was about these whelk egg cases. We have two types in the upper Mid-Atlantic and the Northeast.

The pinched edges of these capsules mean this it the egg case of the Channeled Whelk/Busycotypus canaliculatus.

Here’s one of the capsules separated from the chain. Often these are empty, or filled with sand, or tiny broken bits of shell.

Sometimes, the baby shells are still within. They never made it out before the string washed ashore.

Some of the 3mm long shells from the capsule. The dark spots within are the late whelks themselves.

I examined about two dozen of these egg cases in hope of finding a Knobbed Whelk egg case for comparison purposes. Busycon carica egg capsules have squared-off edges, making them look like thick coins. I didn’t find any. But I did find some passengers on the exteriors of the Channeled egg capsules. Here’s a barnacle. Take a look at that second image again above. There’s a Parchment Tubeworm casing in the middle of the image.

I also found this tiny, 2mm long snail shell attached to the exterior. I think this is the shell of the grass snail Vallonia excentrica, but that’s a land species, so I’m not sure why it was stuck to the capsule on a egg case string in the wrack.

Additionally, I found a number of small white mostly round blobs wedged in between the capsules. I wasn’t until I took off my gloves and pressed one that I realized it was styrofoam.

Here’s another beach in the Lower Bay.

Damned stuff will last for centuries upon centuries.

7 Responses to “Egg Case”

  1. 1 Patty January 31, 2023 at 8:18 am

    Details I didn’t know about something I’ve “known” about for a lifetime!

  2. 2 constance wolf January 31, 2023 at 8:50 am


    div dir=”ltr”>But Matthew,


    div>How do they produce these egg cases? I used th

  3. 4 nature969 January 31, 2023 at 10:32 am

    Great post. But I think people will figure out the styrofoam problem sooner than you predict. 🙂

  4. 5 Chuck McAlexander January 31, 2023 at 12:33 pm

    We are choking on our opwn effluent and refuse to do anything about it because it “costs too much”. What is the price of a new planet. Or, can we find a lightly used one nearby and inhabit it the same way we spread to the rest of this planet? Humans should not be allowed to live off of Earth. E.T. are you listening? Something evil your way comes.

  5. 6 Paul Lamb February 1, 2023 at 5:24 am

    It is surprising to me that something this “large” can be produced by the comparatively “small” whelk.

  6. 7 Monica M February 1, 2023 at 12:40 pm

    Amazing mother nature. Wow!

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