230 



BRANCH CHORDATA 



it is spotted with small white specks. When swimming, the limbs are folded 

 back. 



The other species (I'seudobran'chus stria' tus) is only about 7 inches in 

 length and has three digits to each fore foot. 



Fig. 188. Mud-puppy. (Chapin and Rettger, Englehard & Co., Pub- 

 lishers.) 



The family Prote'idae consists of amphibians having three pairs of per- 

 sistent gills, two pairs of weak limbs with four digits to each one, or the 



Fig. 189. Pro'teus angui'nus. Europe. (From Dodge's "General Zool- 

 ogy," American Book Co., Publishers.) 



anterior pair with two, and the posterior with three digits. The eyes are 

 without lids and covered by a transparent skin, but are functional. They 

 have teeth on the vomer, mandible, and premaxillaries. 



