116 BULLETIN OF THE 



Cerithidea tenuis Pfeiffer. 



This little shell is perhaps the most abundant ot the lagoon gastropods, and 

 is obviously connected by no very extended links vfith. the open-sea C. costata 

 Wood, from which it differs by its smaller and thinner shell, and its brighter 

 brown and white coloration, disposed in spiral bands rather than generally 

 diffused as in C. costata. C, tenuis is only known from the lagoons. 



This completes the list of the marine species of Watling Island lagoon, and, 

 as far as known, the same forms appear in other lagoons of the Baliamas, 

 though much exploration is still needed to make the enumeration exhaustive. 



THE TERRESTRIAL SPECIES. 



These are certainly less influenced by the special conditions of the lagoon 

 than those species which live immersed in its waters ; yet the conditions re- 

 ferred to do aft'ect all species exposed to them, and the terrestrial fauna is for 

 this reason not without its peculiarities. Several of the species are confined to 

 analogous localities in the same general region, and in this sense most of them 

 are very local. A few of those found are very widely distributed, V)ut these 

 may be accidental for this particular locality. The presence of a Planorhis, 

 the only representative of a fresh-water fauna, is highly interesting, though not 

 as inexplicable as the presence of Physa in the rain-water tanks at Bermuda, 

 which was demonstrated by the observations of Dr. G. Brown Goode, and at 

 Arthurstown, Cat Island, where a specimen was collected by Dr. Brown. 



Helix (Microphysa) vortex Pfeiffer. 



Apparently not uncommon. It is native to most of the region between 

 Barbados and South Florida. 



Strobilops Hubbardi Brown. 



Two specimens of this well marked little shell were found. Its range is 

 known to extend from Savannah, Georgia, west to Texas, and south to Florida, 

 as well as on the island of Jamaica. 



Pupa pellucida Per. (P.jamaicensts'l C. B. Adams). 



Apparently not uncommon. Its known range is doubtful, as P. servilis 

 Gould, a very distinct species, has often been confounded with Pfeiffer's shell. 

 The Pupidfe of the West Indies are still in need of much elucidation. The 

 present form is not known from the P'nited States, but very closely resembles 

 a species described from .Jamaica by C B. Adams. 



