Bats allied to Oiyzomys and Rhipidomys. 197 



5. Inomys, gen. nov. 



External characters as in Thomasomys ; mammae not 

 known. 



Skull recalling in shape that of Oxyniycturus or Microxus, 

 with broad low rounded brain-case and long narrow snout. 

 Interorbital region smoothly rounded. Incisors small and 

 delicate. 



Molars rather narrow, their crowns higher than in any 

 other of the genera now dealt with. Their foldings, how- 

 ever, essentially as in Oryzomys and all the present group of 

 genera, not as in Oxymycturus. 



Range. Central Peru. (Only known from Vitoc.) 



Genotype and only species. Inomys incanus, 'Ihos. {Ory- 

 zomys incunus, Thos.). 



The distinction of this genus rests mainly on the peculiar 

 shape of the skull, which, with its broad low brain-case, 

 long narrow snout, rounded interorbital region, and small 

 incisors curiously recalls that of an Oxymycturus or Microxus. 

 Its molars, however, show the typical structure of the 

 molars of the present group, and its interparietal is of full 

 norm^d size. Its removal from Thomasomys renders far 

 more uniform the skull-shape of the species to be referred 

 to that genus, as it was the one outstanding species in this 

 respect. 



The following is the description of a new subspecies of 

 Delomys : — 



Delomys dorsalis collinus, subsp. n. 



General characters of true dorsalis of Rio Grande do Sul, 

 the colour approximately the same, and the fur similarly 

 soft and rich, and so equally differing from the harsh-furred 

 D. sublineatus of Espiritu Santo. But the size, and especially 

 the size of the teeth, averages greater, the molar tooth-row 

 measuring 5*0 mm. in length, while in a considerable series 

 of true dorsalis this measurement is only 4*5 to 4*7 mm., 

 the teeth of collinus being also perceptibly broader. No 

 doubt the two forms will be found to intergrade, but the 

 difference is so constant locally that it should be recognized 

 by name. In the series available the belly is rather more 

 whitish and less buffy, and the underside of the tail is less 

 decidedly whiter than the upper than is the case in dorsalis. 



Mamiuge in the only female \ — 2 = 6, instead of 3 — 2 = 8 



