316 Physical Geography, etc. 



The total number of species known to inhabit the Bahamas 

 is about 80, of which a few species have not yet been satis- 

 factorily determined or described ;* 20 belong to operculate 

 genera, and the remainder are inoperculates. 



The operculate genera represented are Ctenojpoma^ Oy- 

 dostomus, Cistula,-\ Chondropoma, Trochatella, Helicina 

 Schasicheila and Alcadia. 



The occurrence on the Great Bank, in New providence 

 and Eleuthera, of a Schasicheila (S. BaJiamensis Pf.), is 

 singular, inasmuch as the genus is not otherwise rei)resented 

 in the West Indies. Of the four other known species, three 

 belong to the Mexican fauna ; the habitat of S. minuscula 

 Pf. is unknown. 



The operculates considered, the land shell fauna of the 

 Bahamas is essentiall}- West Indian, and that of the Great 

 Bank closely allied to the Cuban fauna. 



Of the five species (exclusive of Cistula f>cabrosa) on the 

 Great Bank, all of which are confined to it, the three follow- 

 ing are also found in Cuba; Chondropoma canescens Pfr., 

 Trochatella rupestris Pfr., and Alcadia minima Orb. 



There are no Cu))an operculate species east of the Great 

 Bank. Several species of the Crooked Island Bank occur 

 in Inagua, and one on the Turk Bank, while three species 

 are common to the latter and Inagua. 



With respect to the inoperculate species, omitting several, 

 the afiinities of which have not been determined, the follow- 

 ing genera and groups are represented, viz. : Zonites {Con- 

 idusf) ; Helix {Microjphysa, Polygyra^ Thelidomus^ Plagi- 

 OPTYCiiA and Polymita) ; Cylindrella s. s., one species; 

 Macroceranius, two species ; Balirnidus (Liostracus, Mesem- 

 hrinus and Leptomerus^ one species of each) ; Cionella (Lep- 

 tinaria, one species) ; /Stenogyra ( Opeas^ Suhulina, Melan- 



*A complete catalogue of the species, showing their distribution, is in course of 

 preparation and will shortly be published. 



fThe single species C. scahrosa Humph., referred by Sowerby to Providence Island, 

 and bj' Gray to Jamaica, 1 do not know. The names of genera or groups (of the iu- 

 operculates also), most numerously represented, are printed in capital lettei-s. 



