1894.] 241 [Allen. 
Locality unknown. Type, a male, mature individual in alcohol. 
Fig. 1. Museum of the Boston society of natural history. 
Ametrida (A. centurio) was founded by J. E. Gray (Ann. and 
mag. nat. hist., ser. 1, v. 19, p. 407, 1847), apparently on a 
single alcoholic specimen from Brazil. The account is short and 
unsatisfactory. W. Petei's (Monatsber. akad. wiss. Berlin, 
1866, p. 396) more fully redescribed the genus from a single dried 
skin (without locality) in the Leyden museum. G. E. Dobson^ 
(Cat, Chir. Brit, mus., 1878) gives an extended account of Ame- 
trida, but refers to a single individual from Brazil probably the 
type specimen. Peters, contrasting Ametrida with Sphaeronyc- 
teris (Monatsber. akad. wiss. Berlin, 1882, p. 987) employs char- 
acters not used in his first description ; one can only assume that 
additional material had passed under his observation. - 
Thus the bibliograi)hy of the genus is scant. In the long 
period intervening between 1847 and 1898 but two individuals are 
mentioned by authors.^ 
The general aspect is that of a species of Stenoderma, but the 
second metacarpal bone is abruptly bent with a convexity outward. 
All the measurements tend to be larger than A. centurio. The 
third phalanx of the tliird digit is little more than half the length 
of the second. The second phalanx of the fourth digit is longer 
tiian the first. 
' Dobson states that the palatal bone in Ametrida centurio is deficient beliiiul, anil 
since he is in doubt as to the propriety of separating Ametrida from Stenoderma, it is 
probable that this deficiency is similar to that in Stenoderma and amounts to a deep 
sinuosity of the posterior palatal border. In the Leyden specimen, the parts were .«aid to 
be mutilated; yet Peters in his second paper states that the border is scarcely cut out. 
- Sphaeronycteris resembles Ametrida i'l the general shape of the skull, in the 
number of teeth, in the rounded head, in the general shape of the ears and tongue, the 
manner of attachment of the wing membrane to l)asd of toes, in the short calcar, in the 
deeply incised interfem, and in the skin-formations about the nose-leaf. But the nose- 
leaf of itself and the physiognomy are quite distinct. The anterior temporal crest is 
extraordinarily widened; the nose-leaf is surrounded above, and the plicae of the face 
suggest a disposition of parts as in A. centurio. The tragus is more sinuate on the outer 
l)order. The incisive foramen is \er\ small; the posterior border of the palate reaches 
the level of the second molar; the breadth of the basicranium between the cochleae is 
as wide as the exposed portion of the cochleae themselves. The coronoid jirocess of 
the lower jaw is higher than in Ametrida. 
3Sin<;e our knowledge of the genus is as yet imperfect, I have thought it best to give 
the characters of Ametrida centurio as glcMued from Peters. It is as follows : poste- 
rior j)alatal border scarcely incised ; basicranium very small, not so wide as the cochlear 
exposure; anterior temporal crest-marked; interfemoral membrane incised; general 
coloration of the fnr brown. 
rUoCKKDINGS 1;. S. N. II. VOL. XXVI. 10 JIAV, 1894. 
