178 MATTHEW— RECENT. DISCOVERIES OF 



sedentary in habit or otherwise unfavorably situated for dispersal. 

 Time is lacking to discuss these further. 



Two questions are involved in the interpretation of this fauna. 

 First as to former connections between the islands themselves, 

 second as to former connections with the mainland. 



There is considerable to be said in favor of Pleistocene or late 

 Pliocene connections between the greater Antilles, extending as far 

 east as the Anguilla group. In favor of this are the presence of 

 representative species or genera of mammals as follows : 



Nesophontes on Cuba and Porto Rico. 



Solenodon on Cuba and Hayti. 



Miocmis on Cuba and the closely allied Acrafocnus on Porto 

 Rico. 



Boromys and Brotomys on Cuba and Hayti. 



Capromys and Geocapromys on Cuba, Jamaica and one island 

 of the Bahamas, also on Little Swan Island. 



Isolohodon and Plagiodontia on Porto Rico and Hayti. 



Amhlyrhisa on Anguilla and Elasmodontomys on Porto Rico. 



Against such connections are to be cited 



(i) The absence of three out of the four ground sloth types from 

 Porto Rico. 



(2) Limitation of the Capromys group proper to the western 

 islands, of the chinchillids to the eastern islands. 



(3) Representative or replacing types are in some cases closely, 

 in others much more distantly related as between the various islands 

 of the chain. No specific sequence of geographic separation can be 

 formulated that will fit the known facts. In some cases it would 

 call for an earlier separation between Cuba and Hayti, in others 

 between Hayti and Porto Rico. 



On the whole I feel that this question is better left open till we 

 get more data, especially as to the fossil faunas of Hayti and 

 Jamaica. 



As to the second question, of continental connections, it seems 

 to me that the weight of evidence is very heavily against it. There 

 are two broad considerations affecting the matter. First, the geo- 

 logic evidence and the submarine topography, while they do not 

 forbid certain former connections, are on the whole unfavorable to 



