NO. 12 MAMMALS FROM CUBA AND SANTO DOMINGO — MILLER 3 



With the characters of so many genera known it becomes possible 

 to gain some idea of the aspect of the Antillean hystricine fauna. 

 The most noticeable feature of these genera considered as a group is 

 their similarity to the Santa Cruzian and Entrerian rodents which 

 Ameghino and Scott have described and figured. In no instance has 

 the same genus been found in both the West Indies and Argentina 

 or Patagonia ; but the Antillean rodents thus far discovered never 

 show such peculiarities that their remains would appear out of place 

 among those of their extinct southern relatives, while as a whole they 

 would at once be recognized as foreign to the present South American 

 fauna. The large Amblyrhisa has teeth fundamentally more like 

 those of the Entrerian Megamys laurillardi than like those of the 

 living viscacha. Its plantigrade foot indicates relationship with the 

 enormous extinct Patagonian rodents rather than with any existing 

 saltatorial animals. Similarly the teeth of Elasmodoritomys , in spite 

 of their relatively small size, appear from Mr. Anthony's figures to be 

 built on a plan identical with that of the molars of Megamys pata- 

 gonicus (Entrerian), but with the same specialization of the anterior 

 wall of each enamel loop that is seen in the simpler teeth of Am- 

 blyrhisa. In its peculiar outline and in the number and arrangement 

 of the cross-ridges the upper premolar is not unlike the isolated 

 teeth that formed the basis of the genus Discolomys^ (Entrerian). 

 On the other hand all the maxillary teeth of Elasmodontomys differ 

 conspicuously from those of any known hystricine now living. In 

 Hcteropsomys the teeth are much like those of Acaremys (Santa 

 Cruz) except that the crowns are more heightened. Teeth of this 

 same type occur in the recent Cercomys, Carterodon and Euryzy- 

 gomatomys; but the genus Hetcropsomys differs from all the living 

 spiny-rats in the form of the skull, most notably in the small size 

 of the antorbital foramen. Of the newly-discovered Santo Domingan 

 genus the only skull has the teeth so worn that their fundamental 

 structure is no longer clear, but apparently this structure resembled 

 that seen in the Santa Cruzian Sciamys rather than in any living 

 echimyid. In the new genus from Cuba the teeth are, by all essential 

 characters, exactly, like those of the Santa Cruzian Stichomys* 

 Of the three known genera which still exist (if Plagiodontia has 

 not been exterminated within the last few decades), Capromys has 



■ Particularly the specimen figured by Burmeister. Anal. Mus. Nac. Buenos 

 Aires, Vol. 3, pi. 2, fig. 6. 1885. Ameghino, Mam. Fos. Argent., pi. 6, fig. 23. 

 1889. 



* See Scott, Rep. Princeton Univ. Exped. Patagonia, pi. 65, figs. 17 and ig. 



