>  All Recent volutids, tropical and otherwise, are direct developers, i.e.,
>  the early development takes place inside an egg case, and the young hatch
>  as crawling, bottom-dwelling snails (versus many other gastropods that
>  undergo pelagic larval stages.) There is indication in the literature,
>  though, of Cretaceous volutids that had pelagic larvae; this is inferred
>  from the morphology of their protoconchs.

HANSEN, T. A.  1980.  Influence of larval dispersal and geographic distribution on
species longevity in neogastropods. Paleobiology, 6(2):193-207.

argues that some Paleogene volutids still had planktonic larvae, though many other Paleogene species have large bulbous protoconchs that are only known from direct developers.

    Dr. David Campbell
    Old Seashells
    University of Alabama
    Biodiversity & Systematics
    Dept. Biological Sciences
    Box 870345
    Tuscaloosa, AL  35487-0345 USA
    [log in to unmask]

That is Uncle Joe, taken in the masonic regalia of a Grand Exalted Periwinkle of the Mystic Order of Whelks-P.G. Wodehouse, Romance at Droitgate Spa

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