678 



CHIROPTERA 



a- 



Fig. 323. — Dentition of DeSmodus rufus. a, Front 

 view of upper teeth ; 6, left lateral view of upper and 

 lower teeth. 



are employed. The upper incisor is greatly enlarged, and of some- 

 what triangular shape (Fig. 323); the canine, although smaller 

 than the incisor, is large and sharp; but the cheek-teeth are very 

 small, with laterally compressed crowns rising but slightly above 

 the level of the gum, their longitudinally disposed cutting-edges 

 being continuous with the base of the canine and with each other. 

 The lower incisors are small, bifid, and separated from the canine, 



with a space in front. The 

 lower cheek-teeth are nar- 

 row, like those in the upper 

 jaw, but the anterior tooth 

 is slightly larger than the 

 others, and separated by a 

 small space from the canine. 

 Behind the lower incisors 

 the jaw is deeply hollowed 

 out to receive the ex- 

 tremities of the large upper 

 incisors. The exceedingly 

 narrow oesophagus opens at 

 right angles into the slender, intestine-like stomach, which almost 

 immediately terminates on the right, without a distinct pylorus, 

 in the duodenum, but on the left forms a greatly elongated fundus, 

 bent and folded upon itself, appearing at first sight like part of the 

 intestines. This cardiac extremity of the stomach is, for a short 

 distance to the left of the entrance of the oesophagus, still very 

 narrow, but soon increases in size, till near its termination it 

 attains a diameter quite three times that of the short pyloric 

 portion. The length of this cardiac diverticulum of the stomach 

 appears to vary from 2 to 6 inches, the size in each specimen 

 probably depending on the amount of food obtained by the animal 

 before it was captured. 



Dvphylla. 1 — A small true molar in each jaw, and a rudimentary 

 calcar. The single species D. ecaudata inhabits Brazil, and appears 

 to be much less abundant than Desmodus rufus, from which, in 

 addition to the characters already mentioned, it is distinguished by 

 its slightly smaller size, the absence of a groove in the front of the 

 lower lip, the non-development of the interfemoral membrane in the 

 centre, and the peculiar form of the lower incisors, which are much 

 expanded in the direction of the jaws and pectinated, forming a 

 semicircular row touching each other, the outer pair being wider 

 than the inner ones, and having six notches, the inner pair having 

 only three notches. 



Fossil rinjllvstonuttidir. — Remains of Vampyrus spectrum, as well 

 as of several species of Phyllostoma or closely allied types, are found 

 1 Spix, Sim. et Vesp. Brasil, p. GS (1S23). 



