22 ANNALS NEW YORK ACADEMY OF SCIENCES 



Tibia and fibula. — Most of the tibiae lack the distal epiphysis. The 

 greatest length of a complete adult tibia is about 64mm. The digital 

 fossa is very deep, and there is a slight indication of a third trochanter in 

 old individuals (Plate V, Figs. 1-4). The fibulas are all except one more 

 or less fragmentary, lacking the distal epiphysis. The single complete 

 bone has a length of 44 mm. (Plate V, Figs. 5-9) . The bones of the hind 

 limb in Capromys pilorides are about one fifth shorter and much thicker 

 than in Isolohodon. 



Summary 



Isolohodon, like Plagiodontia, is evidently of recent extinction. In the 

 case of Plagiodontia, the only extant specimen, so far as known to me, is 

 the type of the species in the Paris Museum of Natural History, described 

 by F. Cuvier in 1836, to which account all the subsequent references re- 

 vert. Cuvier had apparently only a single specimen, sent to him from 

 Santo Domingo by M. Ricord, from whom Cuvier's brief account of its 

 habits was doubtless derived. It is mentioned as being nocturnal and 

 frugivorous, its flesh as very good to eat, and that for this reason "les 

 Haitiens, qui en sont tres friands, les recherchent si soigneusement, qu'ils 

 ont fini par rendre ces animaux tres rare." In all probability it was soon 

 after completely exterminated. It is also probable that Isolohodon had 

 already become extinct in the neighboring island of Porto Eico, doubtless 

 from a similar cause, and perhaps not long prior to the discovery of the 

 island by Europeans. At least the fresh condition of its remains found 

 in Seiba Cave seems to imply recent extinction. 



