FOSSIL VERTEBRATES IN THE WEST INDIES. 169 



ent. Megalocnus occurs abundantly both at Ciego Montero and the 

 Casimba, but apparently only one species at Ciego Montero, while 

 at the Casimba there may be two or three. The species found at 

 the eastern end of the island agrees better with the Casimba forms 

 than with the Ciego Montero species. Of the smaller forms there 

 are clearly two species of Mesocmts, but I see no proof of more 

 than one of Miocnus or Microcnus. 



All these Cuban ground sloths, along with the Porto Rican genus, 

 are most nearly related to Megalonyx among the continental genera, 

 and may be regarded as co-descendants with it of Eucholccops and 

 Megalonychotherium of the Patagonia Miocene. Microcnus is ap- 

 parently the least closely related ; and the relations between Miocnus 

 and Acratocnus are very close. 



Rodentia. — The fossil rodents are all hystricomorphs related to 

 the South American rodents, but not closely related. There are 

 two groups of them (in a broad sense) each with two or three spe- 

 cies. One is still common on the island, the Hutias with two very 

 closely related genera, Capromys and Geocapromys. Of these Ca- 

 promys is common in the latest cave deposits, but in the older levels 

 of the cave material only Geocapromys. The species in the older 

 levels are all small — some are smaller than any surviving species. 

 The large species appear only at the top. The other group is en- 

 tirely extinct ; it consists of three or more species apparently of a 

 single genus which Mr. Miller has called Boromys. It is related to 

 the spiny rats of South America, but not closely. Capromys on 

 the other hand has a near relative in Venezuela Procapromys. 



None of the Chinchillidse of the eastern Antilles have been found 

 in Cuba. 



Remains of Geocapromys occur rarely in the Ciego Montero and 

 Casimba collections ; they are very abundant in the cave collections. 

 Boromys, although common in the .caves, has not been found at the 

 Casimba or Ciego Montero. Dr. Barbour tells me that there is 

 some reason to believe that this genus still survives in Cuba, although 

 it has not found its way into any scientific collections. 



Reptiles. — In the Ciego Montero collection is a series of fine 

 skulls of crocodiles, which Dr. Barbour regards as all growth stages 

 of the living Cuban crocodile C. rhomhifer. This species has a 



