140 BULLETIN': MUSEUM OF COMPARATIVE ZOOLOGY. 



collections made by Messrs. Barbour,- Brooks, and Warner, include 

 maxillae and a fine series of lower jaws from the caves not only at 

 Limones, Cuba, but from those of the Sierra de Casas, Isle of Pines, 

 as well. Except for greater size, I am unable to find any real differ- 

 ence in the teeth and jaws of the two species. The young of B. offrlla, 

 in which the last molar is unerupted, have a tooth-row as long as that 

 of adult B. iorrei with all four teeth. The crown-area in adults of the 

 former is about thrice that of the latter. The cheek-teeth begin to 

 wear at an early age. One specimen (9,935 M. C. Z.) has pnu and vii 

 only in place, with an unworn luo just emerging, but already the pre- 

 molar is so worn that the secondary enamel-folds are reduced to small, 

 round lakes. TlTe posterior of these is first to disappear, and in old 

 animals the main re-entrants are also reduced to ellipses in the anterior 

 teeth (Plate 1, fig. 6) l^efore the secondary folds are quite gone from 

 the posterior pair. The incisors are bright orange on their anterior 

 face. The jaw is of the typical octodont form, but the coronoid process 

 is small, the condylar process low and rounded, the angulare long and 

 tapering, surpassing the condyle in backward extent. 



The adult specimens give the following measurements: — upper 

 cheek teeth (alveoli) 11.5 mm.; three anterior cheek teeth (crowns) 9; 

 lower cheek teeth (alveoli) 11.5; (crowns) 10.8; lower diastema 9.4; 

 greatest length from condyle of jaw to base of incisor above 37; 

 greatest length from angular process to same point 42; depth of jaw 

 at condyle 17. 



The presence of two closely related species of Boromys in Cuba and 

 Isle of Pines has an interesting parallel in the two (or more) species of 

 Capromys, as well as of crows, among birds. No doubt there were 

 some further differences in structure and habit that do not appear 

 from the fragments at hand. 



Capromys nana G. M. Allen. 



Plate 1, fig. 1-5. 

 Caproviys nana G. M. Allen, Proc. X. E. zuol. club, 1917, 6, p. 54. 



This small species I described lately on the basis of jaw-fragments 

 found in a subfossil condition in cave-deposits at two localities in 

 Cuba, near Limones and in the Sierra de Hato Nuevo. These were 

 collected by Dr. Thomas Barbour during his stay in that island early 



