226 DE. KNUD ANDEESEN ON BATS. [Apr. 7, 



peculiarly shortened (see p. 233). — (3) In two species, A. tiorpis 

 and nanus, the depression and flattening of the rostrum and 

 heightening of the brain-case reach a climax, the rostrum being 

 even very slightly bent upwai-ds (profile of iiasals rather a little 

 ascending than horizontal), the palate shortened (see text-fig. 57, 

 on p. 307). 



(B) Teeth. — The species fall into two sections, probably forming 

 two natural branches of the genus : those in which cusp 7 of m^ 

 is compaiatively small, viz. A. glaucus, watsoni, cmereus, and 

 rosenbergi (text-figs. 53, 54, 55) ; and those in which the cusp 

 is comparatively large, viz. A. concolor, planh^ostris, hirsuttis, 

 jamcdcensis, toltecus, quadrivittatits, phceotis, aztectis, turpis, and 

 nanus ; in their exti-emes (upper extreme of the former and 

 lower extreme of the latter section) these two sections come very 

 near to each other. — -The rudimentary upper posterior and lower 

 posterior molar (m^ and m.^) can completely disappear ; con- 

 sequently the number of molars varies between f (A. concolor, 

 planirostris, hirsutus), f (A. jamaicensis, glaucus, toatsoni), and | 

 (A. cinereus, ?'osenbergi, toltecus, quaclrivittatus, phceotis, aztecus, 

 turpis, namos). 



(0) Tragus. — Inner margin thickened, outer margin sharp ; 

 cross-section, therefore, ti^iangular. A notch in the outer margin, 

 at level with base of inner margin ; below this notch a square-shaped 

 lobe, the upper and lower corners of which are 2^roduced into 

 sharp points (this lobe is, in the following pages, called " the basal 

 lobe ") ; above the notch a sharply projecting point (in the following- 

 pages, " the median projection ") ; outer margin, above the median 

 projection, as a rule serrate ; inner margin of tragus perfectly simple 

 from base to tip. In so far the tragus of Artibeus does not differ 

 appreciably from that of Uroderma. — The number of serrations on 

 the upper half of the outer margin, above the median projection, 

 is practically the same in all species but one, varying between 

 and 5 ; the variations within these limits is not specific, but indi- 

 vidual ; the usual number is 4, 3, or 2 ; sometimes the serrations 

 are sharp, very often rounded, often reduced to very small 

 nodules, this latter leading, in extreme cases, to complete obliter- 

 ation of some, or all, of the serrations. In A. concolor I have 

 found the number of serrations to be 7-8, but only one specimen 

 has been available for examination. 



(D) Nose-leaves. — In all species but two the front margin 

 of the horseshoe is free; in A. planirostris it is sometimes, in 

 A. jamaicensis often fastened down to, or even perfectly con- 

 tinuous with, the integument of the muzzle. In no species is the 

 lancet so short as in Enchisthenes harti. 



(E) Wing-structure. — Broadly speaking the wing- structure is 

 the same in all species : fifth metacarpal averaging a trifle longer 

 than third, fourth slightly, the longest ; second phalanx of third 

 digit a little less than, or equal to, or a little more than 1| the 

 length of the first phalanx. — The specific variation chiefiy aflfects 

 the proportionate length of the first phalanx of the third, fourth, 



