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Vol. VI - 
54 ALLEN — AN EXTINCT CUBAN CAPROMYS 
hensilis, mainly immature. Their scattered and fragmentary 
condition may be explained in part by the probability that the 
animals from which they came were brought thither by owls, and 
either they were torn apart in the cave or their bones were re- 
gurgitated as owl ‘pellets.’ 
In examining the material brought back from this cave and from 
the Macha cave, near Limones, several jaws of a very small Ca- 
promys were discovered, apparently representing an undescribed 
species which in life could hardly have been much larger than an 
adult house rat. Even the youngest Capromys prehensilis avail- 
able, in which the last lower molar has just reached the tooth-row, 
has much larger and broader teeth, and a longer tooth-row, than 
the old adult of this small species. A young or immature Jaw of 
this genus is easily recognized by the nature of the bony capsule 
surrounding the last molar; it is thin and porous in texture, and 
its outline is rounded. In an adult, however, the bony alveolar 
wall is solid, its posterior edge thickened to form a narrow ledge, 
and produced backward as a vertical keel. This dwarf species 
may be known as 
Capromys nana, sp. nov. 
Type.— A right lower mandible, no. 9864, Mus. Comp. Zodl., from a 
cave deposit in the Sierra de Hato Nuevo, Province of Matanzas, Cuba, 
collected by Thomas Barbour. 
Specific characters— A small species with a tooth-row about two thirds 
the length of that in the adult C. prehensilis, and with proportionally 
narrower teeth; angular process of the jaw, however, relatively shorter 
and broader. 
Description.— The type jaw retains all the teeth, but the coronoid and 
angular processes are broken off. The strikingly narrower and smaller 
teeth, as compared with C. prehensilis, the smallest of the living species, 
and the less massive proportions of the jaw, are characteristic, and are 
well brought out in the measurements given below. The enamel pattern 
of the teeth is essentially similar, except that the anterior point of the 
first molariform tooth is nearly in the axis of the tooth-row instead of 
nearer its inner border. The shape of the angular process is characteristic. 
