482 ZOOLOGY. 



is from the tertiary deposits of Alabama, which must have reached a very 

 large size. Another, smaller, is from South Carolina. 



The Trichechidce, or walruses, which we have already described among 

 Herbivora, were formerly placed near the seals among Pinnipedia. 



The fiimily of Tlydrarchidce was established^or an extinct genus {Hydrar- 

 chos), which at first was supposed to have been the most gigantic creature 

 ever called into existence. Indeed it was one of the largest at the time 

 when it lived, but its remains have been found to belong to the genus 

 Basilos.iurus, or Phocodon. 



Group 2. Unguiculata. 



This group is composed of those mammals whose food consists chiefly 

 of flesh, generally of a living prey, which they devour with more or less 

 avidity. Some of them, however, the bears for examj^le, have almost a 

 frugivorous diet, eating flesh only by necessity. To these habits corre- 

 spond a set of teeth fitted for the wants of the animals. The incisors and 

 canines are adapted to seize a prey to the best advantage, and the molars 

 to tear it into pieces. The limbs are sometimes short, and sometimes 

 moderately long, never out of proportion ; always strong built, either for 

 the purpose of running after prey or of leaping upon it. The Unguiculata 

 may be divided into two tribes. 



Tribe 1. Plantigrada. 



The animals of this tribe, when walking, place the whole sole of the foot 

 on the ground, a circumstance which enables them to stand vertically 

 upon their hind feet. They partake of the slowness and nocturnal life 

 of the Insectivora. ^They are all provided with five toes to each foot. 

 Most of those that inhabit cold countries pass the Avinter in a state of 

 torpor. "* 



Fam. 1. Ursid^e, contains but one genus, Ursiis (or bears), characterized 

 by a large head, a body and limbs large and powerful, the body itself 

 covered with long and shaggy hairs. The tail is very short. There is no 

 glandular pouch. The number of the molars is variable, the four last a,re 

 large and tuberculous. Several species of bears are found in North 

 America. In common Avith the old continent there is the polar white 

 bear, U. marttimus {pi. 114, Jig. 11), which inhabits the Arctic seas. 

 The black bear, U. americanus {pi. 116, fig. 10), inhabits the east and 

 north of the United States, whilst in the western regions we have the 

 grisly bear {TJ. ferox). The brown bear of Europe {U. ardos) is repre- 

 sented in pi. 116, fig. 9. Several other black bears are found in the East 

 Indies. 



The species of this genus were very numerous during the tertiary epoch, 

 and their remains are found in nearly all bone caverns, especially in 

 Europe. They have also existed in Brazil and the East Indies. 

 686 



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