12 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 8l 



Tyto glaucops cajjable of subsisting" on introchiced rats and mice, 

 and on the native bats, lizards and small birds. Beneath a ledge in 

 one of the caves near St. Michel I found pellets of the small owl on 

 the surface, and, at a depth of from eighteen inches to two feet, 

 compactly moulded masses of extinct rodent bones, evidently parts 

 of the pellets of the extinct bird which once used this same resting 

 place. 



BROTOMYS VORATUS Miller 

 Plate 2, fig. I 



Two imperfect skulls and 52 mandibles. These sjx'cimens represent 

 all the caves worked in with the exception of the deep cave near the 

 Atalaye plantation. 



The skulls essentially agree with the type, from the Dominican 

 Republic. The mandibles, when com|)ared with specimens of Boromys 

 offcla and B. torrci collected in Cuba by William Palmer in 191 7 

 show no striking peculiarities. In both species of Boromys, however, 

 the masseter ridge on the outer side of the mandible is so developed 

 that, in the region beneath nio, its upper surface projects almost at a 

 right angle to the outer surface of the mandilile above it, while its 

 extreme edge in some specimens is slightly turned upward. In 

 Brotoinys the upper surface of the ridge slopes obliquely downward 

 and the margin is not upturned. 



The three genera Brotoinys, the Cuban Boromys, and the Porto 

 Rican Hctcropsomys are at once distinguishable from the other native 

 Antillean rodents by their relatively low crowned, long rooted, 

 subterete cheekteeth. All three are intimately related and it may 

 eventually be found expedient to unite them under one name. For 

 the present, however, it seems preferable to regard them as distinct 

 from each other. The additional material now at hand makes it 

 possible to define their differences as follows: 



Posterior termination of incisor root visible behind anterior base of 

 zygoma when skull is viewed from below ; antorbital foramen rela- 

 tively small, its height much less than length of toothrow Hetcropsomys. 



Posterior termination of incisor root not visible behind anterior base 

 of zygoma when skull is viewed from below ; antorbital foramen 

 relatively large, its height nearly equal to length of toothrow. 



A deep neural channel on floor of antorbital foramen ; posterior 



termination of incisor root marked by an obvious swelling. . . .Boromys. 

 No definite neural channel on floor of antorbital foramen ; pos- 

 terior termination of incisor root not marked by an obvious 

 swelling Broiomys. 



