It depends entirely on the species. NZ's C. costata is always
spirally corded, and C. radiata (extinct) is often so. The latter was
a soft-sediment dweller, so scallop ribbing cannot be the cause.

Of course some would argue that NZ forms are not Crepidula...

>David,
>
>Yes, the second theory is probably the right answer.
>
>Peter
>
>
>At 05:57 PM 7/22/2002 -0700, you wrote:
>
>>I had the impression that the scallop pattern on the dorsal surface of
>>Crepidula was due to lying directly against the surface of a pecten.
>>
>>Now I think it's more likely that the pattern is due to a Crepidula
>>following the ribs of the scallop on which it is attached. The surface of
>>the scallop "guides" the development of the Crepidula's edge.
>>

--
Andrew Grebneff
165 Evans St, Dunedin 9001, New Zealand
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