4i6 Quarterly Journal of Conchology. 



DISTRIBUTION OF CREPIDULA ACULEATA, 



Gmel, 



By J. S. GIBBONS, M.B. 



At page 335 of the Q.J. C. Mr. Garrett alludes to the occur- 

 rence of this species in several widely separated parts of the 

 world. West Africa, Patagonia, and the East and West Coasts of 

 South America may be added to the list there given of recorded 

 localities. Specimens collected by me in the West Indies and at 

 the Cape of Good Hope do not differ materially from Peruvian 

 shells. It is difficult to account for this great diffusion. Some 

 have suggested that it has been effected through the agency of 

 ships and floating logs, but the depth at which the animals live 

 does away with the possibility of the last being a means, and its 

 abundance wherever found, renders it highly improbable that ships 

 can have produced such results. Another theory, but, so far as I 

 am aware unsupported at present by observed facts, is that of the 

 late Dr. Gray. He is of opinion that the (7//rt';r;///r large geograph- 

 ical distribution of some members of the genus, is owing to 

 species possessing a similar variety in different localities; the 

 general form of the shell and the structure of its surface being 

 influenced by the depth of water and the character of the substance 

 to which it is attached. 



Jim, 1878. 



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