282 Descriptive Zoology. 



The Weasels. These are by some placed with the bears, 

 while others ally them to the cats. In this family are the 

 weasel, mink, ermine, marten, ferret, otter, badger, wolver- 

 ine, skunk. All are valuable for their fur. The weasel 

 turns white in winter. Most of these have strong scent 

 glands. Several of them are excellent swimmers and 

 divers, living largely on fish. One otter lives in the sea. 



The Seals. The seals are fitted for aquatic life by hav- 

 ing the hands and feet developed as paddles or " flippers," 

 the limbs being very short. The sea lion can walk on all 

 fours ; others have the hind limbs permanently turned 

 backward, forming a sort of "tail fin," so that they swim 

 very much like the fishes, on which they feed. Seals are 

 sometimes said to be pinnigrade (walking by fins) in con- 

 trast to the digitigrades and plantigrades. No seals in- 

 habit the tropics. The seal grounds of the southern 

 hemisphere have been depleted by indiscriminate killing, 

 and the northern fields bid fair to meet the same fate. 



The Primates. This order, highest of all the mam- 

 mals, includes the monkeys, apes, and man. There is a 

 great range from the little squirrel-like marmoset to the 

 massive gorilla, and from the horizontal-bodied, four-footed . 

 lemur to the erect biped, man. But structure is the basis 

 of classification, and many of these lower forms have 

 almost bone for bone and muscle for muscle similar to 

 those of man. The higher apes are tailless. The form 

 differs greatly, the facial angle of the ape being almost 

 that of a dog, while the Caucasian has an angle of about 

 95. As we approach man in the scale the body becomes 

 more erect and is supported on the flat sole, instead of on 

 the outer edges as in the lower forms. Man alone has a 

 well-developed hand, and he distances all other forms in 

 having the power of speech, although some authors think 



