Zoological Societrj. 69 



angular, smooth-edged wart, grooved in front. Wings broad; 

 thumb rather elongated; the first joint webbed. Interfemoral 

 membrane large, truncated ; the heel-bones long ; feet free to the 

 ankles ; largest toes subequal. Tail elongate, ta])ering, enclosed 

 in the membrane with the exception of the last joint, which is 

 produced beyond the edge. 



Macrotus Waterhousii. Macr. colore murino, ahdomine palli- 

 diore ; prosthemate lanceolato. 



unc. lin. 

 Longitudo ab apice rostri ad caudse basin . . 2 6 



Cauda 1 2 



■ auris , 1 2 



poinds 6y 



prosthematis 5 



antibrachii 2 2 



tibide Oil 



calcaris 6 



Hah. Hayti. 



The interfemoral membrane, in this Bat, has a muscular band on 

 •each side, situated about one-third of the distance between the base 

 of the tail and the heel-bone. The ears are rounded at the apex, 

 and slightly hairy. The tragus is of an ovate-lanceolate form, has 

 an acute tip, and a very indistinct notch near the base on the outer 

 side. 



Mr. Gray has since received specimens of this species from Jamaica, 

 where it was discovered by Dr. Parnell ; this and the two following 

 species are indicated under the name here used in the recently pub- 

 lished list of the Mammalia in the British Museum. 



Mr. Gray next proceeds to make some observations upon a species 

 of Porcupine in the collection of the British Museum. This animal 

 is the Hystrix subspinosus of Lichtenstein, and has been described 

 under that name by Kuhl. It however presents various important 

 modifications in the structure of the skull and teeth, upon which 

 Mr. Gray thinks it desirable to establish a new genus under the 

 name of 



Ch^etomys. 

 The body and limbs are covered with subequal, short, and rather 

 flexible spines. The tail is of an elongate conical form, and provided 

 with rings of square scales and scattered bristles. 



The skull is short, and has broad, convex, swollen zygomatic 

 arches, and the palate is contracted. The cutting teeth are rounded 



4 — 4 

 m front; the grinders are j^^j each grinder of the upper jaw has 



two principal folded plates of enamel and a smaller transverse fold 

 between them. The lower grinders are oblong, and the foremost of 

 these teeth presents two roundish rings of enamel, each of which has 

 an internal fold, and the hinder ring has moreover a small fold on 

 the fore part of the outer side. Each of the other molars in this jaw 

 is furnished with two sinuous folds on the inner side and one on the 

 middle of the outer edge. Of this animal (which is from Brazil) a 



