398 F.MBA.LL0NUR1D.E. 



2. Noctilio albiventer. 



Noctilio albiventer, Spix, Simiar. et Vespert. BrasU. p. 58, figs 2 & 3 

 (1823) ; Peters, MB. Akad. Berl. 1865, p. 670, pi. figs. 2, 2 a. 



Noctilio afiinis, D'Orbir/nj/ et Gervais, I. c. p. 11, pi. 10. fio-. r. 



Noctilio leporinus, Qervais, Expedition du Comtede CaMnau.Zooloaie 

 pi. 12. fig. Qh (s]mll) (vide Peters, I.e.). ' y > 



Much smaller than N. leporinus, and with a comparatively much 

 shorter foot, the muzzle is also comparatively shorter, the fur 

 slightly different in colour, and, as pointed out by Dr. Peters, the 

 skull shovs^s important differences by which this species can be alone 

 distinguished. In other respects, in the form of the ear-conch and 

 tragus, in the very peculiarly shaped extremity of the muzzle, in the 

 cutaneous ridges on the chin and beneath the lower jaw (Plate XX. 

 fig. 9), and in the number and general shape of the teeth, this 

 species resembles N. leporinus very closely, so closely that on a 

 superficial examination it would, most probably, be confounded with 

 not fully grown specimens of that species. Indeed, externally, the 

 only character by which this species may be at once distinguished is 

 found in the conspicuously shorter foot, which is scarcely more than 

 half the length of that in N. leporinus, although the forearm in 

 adult specimens is not more than an inch shorter than in that 

 species. 



Fur bright reddish yellow above, with or without a spinal line as 

 in N. leporinus ; beneath, pale yellowish white, slightly darker on 

 the sides. 



Incisors, canines, and premolars as in N. leporinus, but the upper 

 molars are close together by their bases, and the antero-internal 

 cusps of the lower molars are consequently much less developed in a 

 vertical direction than in that species, where space exists between 

 the bases of the upper molars to receive them when the jaws are 

 closed. 



The skull differs greatly from that of N. leporinus in the remark- 

 able development of the sagittal crest and of the mastoid and par- 

 occipital processes. The sagittal crest in the centre is nearly one 

 tenth of an inch in height, and at its union behind with the 

 superior angle of the occipital crest forms a large protuberance, 

 which projects backwards and overhangs the concave supraoccipital. 

 In N. leporinus the sagittal crest is well developed, but not quarter 

 the height of that in this species, and the occipital protuberance is 

 small, and does not overhang the supraoccipital. 



(For measurements see Table, p. 399.) 



The above description is taken from an adult male, preserved in 

 alcohol, which, in measurements and in general characters, agrees 

 with the type of N. albiventer, Spix, as described by Peters. The 

 fur is, however, unicoloured above, without dorsal white stripe, and 

 the infraorbital foramen is placed in the same relative position as 

 in N. leporinus, or even slightly higher up, not level with the zygo- 

 matic arch as in the type of N. albiventer. This, therefore, may be 

 an example of the variety described as N. ruber by Eengger 

 (Saugeth. Paraguay, p. 95), which agrees in size with Spix's type. 



