70 REPORT 1841. 



On a New Glirine Animal from Mexico. Hy J. E. Gray, F.IR.S, 



The British Museum having lately received from Mr. John Phillips, of the Reale del 

 Monte Mining Company, a new glirine animal, which he brought from Mexico, I am 

 desirous of mentioning it before this meeting, not only on account of its being new to 

 our zoological catalogues, but also because it illustrates two interesting facts, one in 

 the geographical distribution of animals, and the other of certain genera being repre- 

 sented in different parts of the world by animals very similar in external appearance, 

 but yet possessing peculiar characters adapting them to their different localities. 



The animal before us is peculiar for having large cheek-pouches, which open ex- 

 ternally on the sides of the cheek. This conformation has only hitherto been ob- 

 served in four genera of glirine animals, which exclusively inhabit the northern half 

 of the American Continent, as the genera Saccophorus, Saccomys, xinthomys, and He- 

 teromys. These cheek-pouches are used by the animals to carry their food, as the 

 Monkeys of the Old World use their internal pouches which are found between their 

 cheeks and the mouths. The first of these genera has been long known ; and it has 

 been believed that their cheek-pouches hung out of the side of the cheek-like pockets ; 

 but this does not appear to be the case with the genus under consideration, or with 

 Anthomys, which was so called because M. F. Cuvier found their cheek-pouches filled 

 with flowers. 



If it was not for these cheek-pouches, the animal before us might be taken for a 

 Jerboa (Dipus), with which it perfectly agrees in the softness and colour of the fur, 

 and in the length of the hind legs and the tail, which has a brush at the end, so that 

 it may be at once distinguished from the other American genera above enumerated, 

 which either have an elongated scaly tail like a rat, or a very short one like a lemming. 

 I am therefore inclined to consider this animal as the American representative of the 

 genus Jerboa {Dipus), which is confined to the more temperate part of Africa, as the 

 genus Harpaloiis is the representative of the same genus in AustraUa. This combina- 

 tion of the forms and colour with the Jerboa, and with the external cheek-pouches of the 

 pouched rat, at once marks this animal as a new genus, which I propose to call Dipo- 

 domys, or Jerboa Rat, designating the species after its discoverer, Dipodomys Phillipii. 



Mr. Gray exhibited a skin of glove leather from Sweden, prepared from the skin 

 of the foetal Rein-deer by tanning with birch bark. 



Account of a Thylacinus, the great Dog-headed Opossum, one of the rarest and 

 largest of the Marsupiate family of Animals. By Professor Owen. 



At the present day this animal exists only in Van Diemen's Land, though formerly it 

 had a much more extensive geographical distribution. For his knowledge of the ana- 

 tomy of this animal, Mr. Owen stated that he was indebted to Sir John Franklin, who 

 had kindly preserved and sent him a specimen in spirit, and he believed this was the 

 only specimen extant in Europe. In its habits it was carnivorous ; holding about the 

 same relatiozi to the other Marsupialia that the digitigrade Carnivora did to the placental 

 Mammalia. It was a great pest to the shepherd in its native districts ; and in its low 

 intellectual character, and its craft and cunning, very much resembled the wolf. In de- 

 stroying sheep it does not feed on them at once, but proceeds to worry, if possible, the 

 whole flock, first tearing one and then another. Its smell is very powerful. It has a 

 narrow head, a large number of incisor teeth, with the molars more numerous and'uni- 

 form in size and shape than in the wolf. The incisors are of equal length and regularly 

 arranged in the segment of a circle, with an interspace in the middle of the series of 

 both jaws. The external incisors on each side are the strongest. The laniary or canine 

 teeth are long, strong, curved and pointed, like those of the dog tribe. The spurious 

 molars in this, as in all other Marsupials, have two roots ; their crown presents a simple 

 compressed conical form, with a posterior tubercle, which is most developed in the hind- 

 most. The true molars in the upper jaw are unequally triangular, the last being much 

 smaller than the rest; the exterior partof the crown is raised into one large pointed mid- 

 dle cusp and two lateral smaller cusps obscurely developed ; a small strong obtuse cusp 

 projects from the inner side of the crown. The molars of the lower jaw are compressed, 

 tricuspidate, the middle cusp being the longest, especially in the two last molars, which 

 resemble closely the sectorial teeth (dents carnassiers) of the dog and cat. The fol- 



