Data: I am trying to identify the snails that made these egg cases in my backyard in Seattle Washington. I found the cases in the ground in a shady place in early September. At first they are closed, but in a few days they open on top as you see in the photo. I looked at the little "eggs" under a microscope (I am a biology teacher), and they seem to be baby snails. I've never seen snails in my yard before, only slugs.

Any ideas?    Thanks so much!
Fayla S.

Send Ideas to: Fayla

Identified: After much thinking about the whole thing and reading everyone's comments, I remembered an interesting fungus that I saw only once, called a birds nest fungus (Cyathus stercoreus). That is exactly what I have here. The reason I was not thinking fungus was that the small structures inside the cups are much too large to be fungal spores - but birds nest fungi have their spores in little packets called peridioles, and that is what I'm seeing. The soft flexible "bodies" extending from the peridioles are an attachment to the side of the cup that deteriorates as the fungus develops....Fayla

Discussions:

• I know of no snails or slugs with egg cases such as these. Eggs of snails and slugs are spherical to oblong and are laid singly or (in most garden species) in clusters of a few to many eggs. I'm unable to say what the cases are, but the 'baby' snails may in fact not be juveniles. It's difficult to see from your photo, but the colour and shape suggest a species of Vallonia (perhaps either V. excentrica or V. pulchella), common in gardens and waste places. Vallonia spp. are rather flatly coiled, white snails < 2.8 mm across. That's what I suggest. I'd be interested in learning what others conclude...Regards, Robert F.

• I believe that these are fungus 'fruit', not unlike mushrooms. I have never come across egg cases for terrestrial snails, but unless she opened one up and found it full of baby snails, I would not believe it. I would believe that snails would crawl in to eat it. ...
  Allen A.

• These are not snail eggs but a fungus, Cyathus olla, commonly known as "bird's nest fungus". More information here for anyone who is interested: http://waynesword.palomar.edu/pljune96.htm ....Paul M.

• I agree with Paul and Allen that they are a type of micro-fungi. Even here in Israel we have similar types of fungi growing on dead branches laying on the ground during the rainy period... Henk K. M.

• My 2 cents' worth: they "explode" when hit by rain and the spores attach to house siding and are nearly impossible to remove. They grow on wood mulch. Get them far away from the house! ...John W.

• Those are a sort of Mushroom (Fungi). !! ...Wiggers