280 bulletin: museum of comparative zoology. 



shape, in which were included the Bahamas, Florida, Cuba, San Domingo, 

 Porto Rico, and the Virgin Islands." 



Mr. Agassiz, however (p. 116), finally tends toward opinions very 

 similar to those of Hill : 



" The deep soundings (over three thousand fathoms) developed by the 

 'Blake' south of Cuba, between that island and Yucatan and Jamaica 

 do not lend much support to the theory of an Antillean coutinent as 

 mapped out by Wallace, nor is it probable that this continent had a 

 much greater extension in former times than now, judging from the 

 depths found on both sides of the West India Islands. This would all 

 tend to prove the want of close connection between the West India 

 Islands and the adjoining continent. It leads us to look, for the origin 

 of the fauna and flora of those islands, to causes similar to those which 

 have acted upon oceanic islands. The proximity of these islands to a 

 great continent has, however, intensified the efficiency of these causes." 



If we grant for the sake of argument that the Greater Antilles, like all 

 Oceanic Islands, have received their fauna fortuitously, we must then 

 explain the regularity and consistency with which the fauna has spread 

 from two directions to populate such a great number of separate islands, 

 with and against the prevailing wind and current. We find in the Les- 

 ser Antilles that the fauna is of almost purely Northwest South American 

 origin ; as we pass thence to St. Thomas and to Porto Rico we note, as 

 Stejneger has shown, the very evident two-fold origin already mentioned. 

 Then in Jamaica and Cuba the balance is in the opposite direction — 

 types of Central American origin predominate. The ancestry of Crico- 

 saura, Amphisbtena, Bufo, and other forms prove that migration to these 

 two islands took place along independent land bridges. The fact that 

 the Jamaican coney belongs to a different section of the genus (Capromys) 

 similar to the Haitian and different from the Cuban species, and that 

 Solenodon occurs in Cuba and Haiti and not now or so far as we know 

 ever in Jamaica, pi'oves or helps to prove the independent connection with 

 Haiti of both Cuba and Jamaica. Finally, in favor of the " bridge the- 

 ory " Dr. Stejneger in a recent letter writes : " Whatever the mountain 

 structure may show, certainly the geographical distribution of the ani- 

 mals shows that the Greater Antilles have been part of a continent at 

 some time." 



That Dr. Stejneger's opinion represents views which are gaining con- 

 stantly in credence among present-day students of zoogeography there 

 can be no doubt. Dr. R. F. Scharff in his " History of the European 

 Fauna" (London, 1899) cites many experiments to show that land snails 



