NATURAL SCIENCES OF PHILADELPHIA. 157 



portion of the temporal fossre. Occipital ridge well marked and leaning back- 

 wards. Foramen magnum orbicular. Palatal bones united with the deeply 

 arched mouth by a greater angle than that of Pteropus. The foramen incisi- 

 Tum is cordate. 



The lower jaw is flattened and irregular, depressed at symphysis. The two 

 halves unite at a less acute angle than in Pteropus. The coronoid process is low, 

 and the angle which it forms with the alveolar ridge is so slight that the dis- 

 tance from the top of the process to the last molar is equal to one half the 

 distance from the same point to the small pre-molar. The condyloid process 

 is about one-half the distance between the base of the jaw and the top of the 

 coronoid. 



The superior incisors are small unicuspid, regular and separated from one 

 another. The distance between the canines and the laterals is greater than 

 the distance from one incisor to another. The canines are slender, convex 

 anteriorly, point slightly backward, and, when the jaws are closed, nearly 

 touch the plane on which the skull rests. The first molar is pointed ; the 

 second and third are much alike, the posterior being smaller and less trenchant, 

 the external cusp being the larger. 



The inferior incisors are small, separated, the space between the centrals 

 exceeding that between the laterals. The canines are smaller and blunter 

 than those above, and lean strongly backwards. The premolar, which is ab- 

 sent above, is here present ; it is very minute, shaped, like an incisor, is 

 nearer the canine than the second molar, is directed backward and outward, 

 and, when the jaws are closed, is observed to be placed anterior to the superior 

 cuspidatus. The first and second molars assume the carnivorous type ; the 

 second has two cusps divided as usual by a longitudinal groove ; the third 

 and fourth have their cusps much worn, the latter being little more than flat- 

 tened tubercles. 



As mentioned above, the articulation is curious ; the inferior incisors close 

 in front of the superior, so as to completely hide them. 



H. monstrosus, n. s. Fur fine and short, very thin upon the face, inter- 

 spersed with a few long stiff hairs. A well-marked white line extends from 

 the facial protuberance to between the eyes. Top of head and nucleal region 

 light ash brown, dark in the centre, lighter upon the sides, and narrowing to 

 a whitish band which encompasses the inferior part of the anterior surface of 

 the neck. The hair between this band and the chin is very thin and scatter- 

 ing, and of a pale brown. Dorsum delicate plumbeous tipped with grey, thicker 

 above than below. The fur runs to a purer brown upon the posterior part of 

 interfemoral membranes and thighs. The fore extremities to near the carpal 

 joint are clothed with a thin coating of fur, while the interbrachial surface and 

 that contained between the fourth finger and the sides of the body are studded 

 in different directions with interrupted lines of minute hairs. The pectoral 

 region and sides of belly of the prevailing hue plumbeous grey with a ten- 

 dency of that in the centre of the abdomen to become whitish. Pubic region 

 brownish. At the point of junction of the interbrachial membrane with the 

 body a row of white hair is seen. The membranes beneath have upon them 

 the same thin lightish hairs as above, but more extensive. 



The dimensions of the skull are as follows : 



Length from occiput to extremity of nose 2*9 in. 



" of cranium 1*0 



" " nose 1-6 



Height of nose 0*9 



Breadth of nasal bones - 3^ 



" palate between canines 0*6 



" " " molars 09 



Distance between zygomas 1-6 



1861.] 



