182 bulletin: museum of comparative zoology. 



to a less degree, in the case of the West Indian race of Molossus 

 obscurus, which appears to have become slightly differentiated from 

 its prototype of South and Central America. 



The case of Natalus is probably analogous in large measure to that 

 of Nyctirwmus brasilicnsis. This is a genus of tropical America, 

 and in the Antilles is known from San Domingo and Dominica. On 

 the continent it ranges north into central Mexico. In San Domingo 

 the slightly larger size of the representative of N. stramincus has 

 caused it to be described as the race major. In Dominica, however, 

 it seems quite the same as the form of the neighboring South American 

 mainland whence it is supposedly derived. The genus is to be looked 

 for on other of the Greater and Lesser Antilles, and from Jamaica 

 probably rather than from Cuba, since the Yucatan land extension 

 was perhaps slightly too far north to be available for this tropical 

 species as a passageway to Cuba. 



Of the three peculiar West Indian genera that occur in both the 

 Greater and the Lesser Antilles, namely, Monophyllus, Brachyphylla, 

 and Ardops, the first is widespread. Among the Greater Antilles it 

 is known from Jamaica, Cuba, and Porto Rico, on each of which a 

 local race has become differentiated. Doubtless it occurs on San 

 Domingo as well. Among the Lesser Antilles it is represented by a 

 local race on Santa Lucia and on Barbados; and an additional species 

 is described, without locality, but is probably from one of the West 

 Indies. Brachyphylla is recorded from Cuba, St. Vincent, and Bar- 

 bados. The Cuban form is smaller, and is considered a species 

 distinct from that of the Lesser Antilles. Possibly the genus is to 

 be looked for on the intermediate islands. Ardops, with the related 

 genera Phyllops and Ariteus, are doubtless to be considered as a unit 

 in their geographical relationship. Ardops is recorded from Haiti 

 in the Greater Antilles, and from Montserrat, Dominica, and Santa 

 Lucia in the Lesser Antilles. In each of these islands a local form has 

 become differentiated. The closely related Phyllops seems to be the 

 representative of Ardops in Cuba, and in Jamaica its place is similarly 

 taken by the kindred genus Ariteus. The correspondence between 

 the distribution of the endemic genus Monophyllus and the Ardops- 

 Phyllops-Ariteus group is therefore very striking, despite the evident 

 gaps in our knowledge. No representative of Brachyphylla is yet 

 known from Jamaica. It seems very significant, however, that this 

 "most primitive of the Stenodermines" should occur with the genus 

 Monophyllus on Barbados, formerly supposed to be a good example 

 of an 'oceanic' island. The fact that the genus is yet known from 



