318 DR. KNUD ANDERSEN ON BATS. [Apr. 7, 



would leave between the Mosquito Coast and Jamaica only two 

 channels, the wider 75 miles ; these channels would be so narrow 

 as to form no serious barrier for the spreading of a bat. 



(5) The geological line of separation between the Larger and' 

 Lesser Antilles runs, probably*, between the Virgin Islands and 

 Anguilla ; the Virgin Islands therefore belong geologically to the 

 Larger, Anguilla to the Lesser Antilles. Though Antillean and 

 Central American in origin, A. j. jamaicensis has in the course of 

 time crossed this line ; coming from west (Porto Rico) it has 

 spread a little east of the line, at least as far as St. Kitts. But 

 there, or in some neighbouring island, the range of the race seems 

 to terminate ; farther southward in the chain of the Lesser Antilles 

 (Guadeloupe, Dominica) is f oimd a race {A . j. prteceps) which has 

 no direct phylogenetic connection with A. j. jeimaicensis, but is an 

 offshoot of the S. American A. j. palonartmn. 



(6) The direct connection between the northern and southern 

 American continent has given A. j. jeimaicensis the opjDortunity of 

 spreading sovithward, through the Cordilleras, as far as Ecuador, 

 where it has developed into the comparatively large'-sized, large- 

 skullecl, and large-toothed A . j. cequatoriaUs. 



(7) While it is safe to assume that A. j. parvi2)es, yttcatanicus, 

 and jeimaicensis are of " northern," i. e. Central American- 

 Antillean, origin, and A.j. eeqtuitoriedis an Andean offshoot of" 

 this northern branch, it is equally bej^ond doubt that A.j. litureitns 

 and ^j«Z?»r«'?M)i are of S. Ameiican origin, for the following 

 reasons: — first, A. j. 2)cdmeirum., from Venezuela, is so extremely 

 closely related to A.j. liivreitus, from Brazil and Paraguay, as to 

 be, for all practical purpose, indistinguishable ; given that A. j. 

 lituratus is of S. American origin, A.j. pedmarum is therefore the 

 same; second, the range of A. j. peihneirzim extends from Vene- 

 zuela, through C. America to S. Mexico, but the race is completely 

 absent from the Larger Antilles, an evidence that it has reached 

 C. America and Mexico at a time when the Larger Antilles were 

 definitely separated from the mainland ; third, whereas A. j, 

 jameoicensis is common (and equally common) everywhere in 

 C. America and S. Mexico, A. j. p)eilmeir'um becomes rarer and 

 rarer farther north in C. America, until in S. Mexico it is 

 very rare, an additional evidence that A.j. jamaicensis is the 

 indigenous race, A. j. p>eilmeiruni an immigrant from the south. 



(8) The southern gi'ouj:* has spread from the mainland over the 

 WindAvard Islands. Individuals from the Venezuelan coast 

 islands, Trinidad and St. Vincent, are indistinguishable from the 

 continental A.j. peihneirum. But farther north, in Dominica and 

 Guadeloupe, they have developed into a slightly diflerent race, 

 A . j. prceceps. 



* A. Agassiz, Three Cruises of the ' Blake,' i. p. 112 



