911 



MURIDJE. 



MURID^E. 



9(2 



Teeth of Olomyi. T. Cuvier. 



0. unisvlcatua, Caffre Otomys. The anterior limbs have four 

 complete toes, armed with delicate nails, which are compressed and 

 sharp, and a rudiment of an unguiculated thumb ; the posterior feet 

 have fiye toes, armed with the same naila, but the two external ones 

 are very short. The tail is but scantily covered with hairs, and is 

 scaly and short. The muzzle is very thick and obtuse, entirely 

 ' covered with hair, with the exception of a slight ridge round the 

 nostrils, which are small, and approximated to each other below ; the 

 eyes are large, as well as the ears, which have an internal projecting 

 membrane, which, when ita edges (parois) are approximated, entirely 

 shut the entrance of the auditory passage. The mouth is very small, 

 the upper lip cleft, and the tongue thick, short, and covered with 

 soft papillae. There are whiskers on the sides of the muzzle and 

 above the eyes. The fur is thick, very soft, and consists of two sorts 

 of hairs ; the shortest and most numerous, which determine the colour 

 of the animal, are woolly, and, when viewed through a microscope, 

 appear to be formed of very small rings, alternately bright and obscure ; 

 the others, rare and longer than the first, are also stouter and more 

 stiff; these, when viewed through a microscope, present only a uniform 

 texture, and so it is with the whiskers. The woolly hairs are of a 

 slaty-gray for two-thirds of their length, and then of a yellowish- 

 white, with the point black, whence results the dirty yellow tint with 

 which the animal is coloured above; below, yellowish-white pre- 

 dominates. The very short hairs of the tail are of the colour of 

 those of the back ; the extremities have the tint of the under parts. 

 Length about 6 inches (French), from the tip of the muzzle to the 

 origin of the tail, which last measures 34 inches. Mean height, 

 24 inches. (F. Cuvier.) 



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-' :l *w 



Caffre Otomyi (Otomyt unitulcalui}. 



/>> J 8 



' . - 



' -';> 



The habits of this species do not appear to be known, nothing 

 respecting them having been found in the notes of M. Delalande. 

 F. Cuvier thiuks that it is doubtless omnivorous, like the rats ; 



but from the size of its eyes, it may be conjectured that its life is not 

 passed in such obscurity as theirs ; and from the delicacy of its sharp 

 claws, and the softness of its fur, that it does not burrow. 



ffydromyt (Geoffrey). Muzzle rather pointed ; ears small and 

 rounded. Body covered with long hairs. Tail long, cylindrical, rather 

 scaly, with scattered hairs. Four toes and the vestige of a thumb on 

 the fore feet. The hinder feet 5-toed, and palmated for two-thirds of 

 the length of the toes. Molars with the crowns divided into obliquely 

 quadrangular lobes, the summits of which are hollowed into a spoon- 

 shape. 



o o o 



Dental Formula : Incisors. -: Molars, f - = 12. 

 2 22 



Xeeth of Eydromys. F. Cuvier. 



If. leucogatler. It has the fur short, soft, marone-brown above, 

 white below ; tail black at the base and white at the other extremity. 

 Size sometimes twice that of the Common Brown Rat. 



Hydromys leucogaster. 



M. Geoffroy has recorded two species, that described above, and 

 another with a yellow belly, H. chrysogaster ; the last he states to be 

 nearly one-half less than the Coypou, but they are generally considered 

 to be only varieties of the same species. M. Geoffroy speaks highly 

 of the quality of the fur of the yellow-bellied variety, and says that 

 it is more valuable than that of the Coypou. 



The.e animals are aquatic, and were found in the islands of 

 D'Entrecasteaux Channel. That named //. chrysoyaster was killed 

 by a sailor at the moment when it was taking refuge under a heap of 

 stones ; If. leucogastcr was taken in the island Maria, in the same 

 channel. 



True Rats and Mice. 



F. Cuvier ('Dents des Mammiferes') observes that up to the 

 time of his writing, animals provided with the same teeth as the Rat 

 (Mus Rattus), the Brown Rat (Surmulot of the French Mua decu- 

 manus), or the Mouse (if. Musculus), formed a single and very 

 natural genus. He then goes on to state that the possession of a 

 cranium, the origin of which he knows not, in presenting the type of 



