Bibliogrnphical Notices. 371 



tions fifteen species only iis recognized by himself. This, however, 

 raises the nuiiiMor of positively recognized Mammalia belonging to 

 the North American fauna to 235, excluding Pinnipeds and Ce- 

 taceans. 



Taking the several groups in the order in which they stand in 

 Professor Baird's arrangement, we have first the Insectivora, con- 

 taining Shrews and Moles, — together 26 species. Among these is a 

 very remarkable (if reliable) addition to the American fauna in the 

 shape of a second species of Urotrichus, a genus o( Talpidce hitherto 

 embracing but one member, found in Japan. We may, however, 

 notice the fact that but one imperfect specimen of this animal appears 

 as yet to have been obtained ; and an accurate comparison of it with 

 the Japanese Urotrichus is requisite, before animals coming from 

 localities so different can be recognized without doubt as the two 

 only members of the same peculiar genus. 



Of the Carnirora the large number of 4G are recognized as North 

 American, made up of 9 Fefidce, 8 Canidce, the Bassaris astuta of 

 Mexico and Texas — sole representative of the family Viverridce, 

 2.S Mustelidte, and .5 species of Ursidce. This is exclusive of several 

 species established by previous writers, but which Prof. Baird has, 

 with much judgment, reduced to the rank of local varieties— such as 

 tlie Canis nubilus of Say, and the Felis maculata of Ilorsfield and 

 Vigors. 



The MarsKpialia in the northern portion of the American conti- 

 nent are represented by two species of the genus Didelphis, commonly 

 known as ' Opossums.' 



The Rodents are, again, extremely numerous. In the first place, 

 the Squirrels of ditferent genera, with the Marmots (so called), Prairie- 

 dogs, and Beavers, make up no less than 4 1 members of the family 

 Sriuridce. The Saccounjidce, or Pouched Mice, which, in accordance 

 with Mr. Waterhouse's views, but in oi)position to those of Professor 

 Brandt, are grouped together, next follow, and are considered by 

 Professor Baird as " one of the most natural families of Rodentia, 

 although the component genera have been widely separated by dif- 

 ferent authors. In the external cheek-pouches," he remarks, " there 

 is no other family whicli exhibits any approach to it. These open 

 outside of the mouth, and are of variable depth and lined with short 

 hairs to the bottom. When inverted and dried, they look like sacs 

 on each side of the head." Of these peculiar animals, the range of 

 which is confined to Northern America and the Antilles, 21 species 

 are enumerated, as appertinent to the fauna of the United States. 

 Two Porcupines of the North American form Erethizon are the only 

 IlystricidfB met with in this part of the world ; but there are no less 

 than 52 Murid^ of varied forms ; and 13 Hares and Rabbits, with 

 a single Lc^o»??/*, give 14 species of the family Leporidce. Altogether, 

 therefore, the order Rodentia in North America, as elsewhere, plays 

 a most important part as regards numbers, embracing 130 species — 

 more than half the whole number of Mammals known to occur. 



The order Edentata is represented within the limits of the United 

 States bv a single straggling species of Armadillo, which occurs 



24* 



