1888.] NATURAL SCIENCES OF PHILADELPHIA. 323 



of the common form of the eastern United States, Pakemon vulgaris. 

 Whether the species is entirely absent or not I cannot of conrse say, 

 but it is surprising that it should not have been observed by us. 

 Penaeus velutinus, Dana. 



One specimen, which agrees with the figure and description of the 

 species obtained by Dana off the Sandwich Islands (U. S. Exploring 

 Expedition, Crustacea, p. 604), and which was subsequently collect- 

 ed by the Challenger party at various points in the Pacific, and be- 

 tween Australia and New Guinea (Challenger Reports, Zoology, 

 XXIV, p. 253). This species, as well as all the immediately related 

 forms, has, as far as I know, been found thus far only in the Pacific. 

 The case is, therefore, another example of remarkable geographical 

 distribution. 



STOMATOPODA. 



Gonodactylus chiragra, Latr. 

 One specimen from the beach of Flatts Village. 



MOLLVSCA. 



The enumeration of species of molluscous animals is left for a 

 future paper, as our collections, large as they are, are doubtless in 

 great part deficient. Through the kind energies of local collectors 

 I hope to supplement at an early day the material obtained by us 

 and to present, as nearly as is possible, a full list of the species 

 inhabiting the Bermudian waters. We ourselves collected some 110 

 or 120 marine species, which is largely in excess of the number 

 that has thus far l)een chronicled in any list of Bermudian species, 

 but the examination of private collections in the islands satisfies me 

 that there must be an additional 30 or 40 species, or more, that are 

 common to the island group. 



It is a well-known fact that the Bermudian molluscan fauna 

 is distinctly, and it might be said, overwhelmingly Antillean in 

 character, by far the greater number of species being found in 

 the Bahaman and West Indian Seas, or along some part of the coast 

 of Florida. The practically total absence of species of the Eastern 

 United States which are not found in the Floridian waters is aston- 

 ishing, and shows how insuperable is the barrier which the waters of 

 the Atlantic, and of the Gulf Stream particularly, offer to a free 

 migration or dispersion of the species. This, again, appears the more 

 remarkable in the light of certain anomalies of distribution which a 

 critical examination of the species reveals, and which had already 



