ALLEN: MAMMALS OF THE WEST INDIES. 181 



general, there are several. Of these Noctilio leporinus, owing to its 

 fish-eating habits, might be expected to cross narrow stretches of sea, 

 and so to spread from island to island. Its occurrence may therefore 

 not he very significant from a geographical point of view. Probably 

 the best known of the West Indian bats is Artibeus jamaiccnsis, with 

 its races, more or less nominal. It might he thought that so large and 

 strong a species would readily fly far over seas to populate outlying 

 territory, but this supposition is not clearly borne out. The species 

 is apparently absent from the Bahama archipelago, and its supposed 

 occurrence at Key West, Florida, is unsubstantiated. Dr. K. Ander- 

 sen, in his recent study of this genus, considers the Cuban form an 

 admissible subspecies, derived probably from the Yucatan race. 

 Typical jamaiccnsis occurs in the Honduras peninsula, St. Andrew's, 

 Old Providence, and Jamaica, across through San Domingo and 

 Porto Rico, and even so far east as St. Kitts, that is, slightly beyond 

 the supposed geological boundary between the Greater and the Lesser 

 Antilles (namely, the depression between the Virgin Islands and 

 Anguilla. Dr. Andersen admits, however, that there "is absolutely 

 no 'hard-and-fast' line" between jamaiccnsis and the race palmarum, 

 from the latter of which he considers the race praeccps of the northern 

 Lesser Antilles to be derived. The difficulty of determining the 

 exact relationship of these bats may be gathered from the fact that 

 praeccps of Dominica and Guadeloupe is indistinguishable from 

 acquatorialis of Ecuador, which itself is merely a larger edition of 

 typical jamaiccnsis I There can be no doubt, however, that this 

 author is correct in deriving the races palmarum and praeccps from 

 the race of the South American mainland, while the Greater iVntillean 

 representatives came by way of Central America. 



The genera Nyctinomus and Molossus are probably the swiftest 

 flying bats, yet it is remarkable that they show a differentiation in 

 the West Indies that indicates a long continued local habitat. The 

 common Nyctinomus b. musculus of the Greater Antilles (Jamaica, 

 Cuba, San Domingo, and Porto Rico) is a race distinct from that of 

 the adjoining mainland of North and Central America. Among the 

 Bahamas, a further but less marked differentiation has occurred, 

 represented by the race bahamensis; while in the Lesser Antilles, 

 from Barbados north to at least St. Kitts and St. Bartholomew is 

 the race antillularum. The fact that these two or three races should 

 have thus become separated off, while the continental brasilicnsis is 

 the same from Patagonia to Texas, is very significant of the practical 

 absence of recent migration of these animals. The same is true, but 



