196 bulletin: museum of comparative zoology. 



novemcindus from Brazil, but smaller. Skull smaller, with tooth- 

 row decidedly shorter, due in part to the usual suppression of the last 

 molar. 



Description. — The dermal armor in the fresh specimen is flesh color, 

 darkening slightly in the midline. It consists of the usual frontal 

 shield, produced posteriorly between the ears, a scapular and a pelvic 

 shield, with nine transverse movable bands between. The dorsal 

 surface of manus and pes are closely covered with more or less hex- 

 agonal scales. The tail has twelve complete bony rings, succeeded 

 by an armored tip 110 mm. long. From the posterior free edges of 

 the transverse body rings project three or four short bristles from 

 each scale; similar but more minute hairs are present at the posterior 

 margins of the scales on the shields of body and tail. The ventral 

 surface of body and limbs is set with transverse rows of small round 

 dermal scutes that average about a centimeter apart. Each of these 

 scutes is the center of a cluster of yellowish bristles which are longest 

 on the throat and legs. Mammae four, two pectoral, two inguinal. 

 Claws, four on the manus, five on the pes. Ears minutely scaly. 



Skull. — Except for its smaller size, the skull of the West Indian 

 armadillo is very similar in form to that of the mainland animal from 

 Brazil. The premaxillaries, however, average slightly shorter in 

 proportion, and are nearly as long, ventrally, as the distance from their 

 posterior points to the first tooth, instead of greatly exceeding the 

 distance, as is more usual in mainland specimens. The most notable 

 and interesting peculiarity of this island race, however, is the tendency 

 to the reduction of the number and size of the teeth, which thus 

 produces a shortening of the entire tooth-row. The number of teeth 



8—7 8—8 8—8 8—8 8—8 



in five specimens from Brazil is: — gz§; gZg; gZg; gZg; gZg. In the 

 three specimens from Grenada the teeth are: — 



No. 8116, 7 0f, No. 8117, ££; No - 8118 > £S- Xt is the posterior- 

 most tooth of the upper series that has become lost in all cases. This 

 is clearly shown also in the single aberrant Brazilian specimen b}^ the 

 fact that on the left side there is a minute posterior tooth; but on 

 the right side the corresponding position is blank, and the large 

 seventh tooth is exactly opposite the seventh tooth of the left side. 

 In all three Grenada specimens the small posterior tooth is perma- 

 nently lost, so that the tooth row ends abruptly with the large sixth 

 or seventh tooth. In No. 8118, it is also clearly the seventh tooth 

 that has been lost on the right hand side, since the corresponding 

 tooth of the left side is opposite the empty space. Moreover, this 

 dropping out of the posterior members of the series increases the 



