Auchenipterid sperm case

[Jools]

I'm about to post a picture of these things which appear used in the reproduction of Parauchenipterus galeatus and perhaps all woodcats. They appear to be a waxy shell which surrounds the sperm as it is "delivered" into the female. These cases are found in the aquarium. Presumably they are much smaller in smaller woodcats and that all auchipterids produce them. Often they are eaten if not removed.

Questions:

1. Has anyone else observed this.
2. Is there a scientific name for such a thing

Jools

[Silurus]

I think they are called spermatheca (plural: spermathecae). I might have a cool scientific paper describing sperm ultrastructure and fertilization in auchenipterids somewhere.
Email or pm me if anyone is interested and I'll go dig it out.