48 SYNOPTIC KEY 



6(i) Adults not fishlike; always with lungs though some- 

 times with gills in addition. Larvae may be fishHke 

 tadpoles. 7 



7(8) Skin naked and shmy, no scales, feathers or hairs. 



Class Amphibia, p. 49 



8(7) Skin covered by outgrowth consisting of scales, feathers, 

 or hairs or combinations. 9 



9(10, 11) Skin covered with scales, never with hair or feathers. 



Class Reptilia, p. 49 



10(9, 11) Skin covered by feathers and scales; birds (see Reed, 

 Bird Guide or Chapman, Birds of N.E. United States). 



Class Aves 



11(9, 10) Skin covered in part by hairs w^hich may be apparently 

 absent at times; scales may be present; young born 

 alive and suckled with milk from mammary glands, 

 (except Australian species). 



Class Mammalia, p. 50 



Class CYCLOSTOMATA 



1(2) Buccal tentacles present, eyes degenerate; intestine 

 without spiral valve; marine. 



Subclass Myxinoidea 



2(1) No buccal tentacles; eyes well developed; intestine 

 with a rudimentary spiral valve. (Forbes and Richard- 

 son, 5.) Subclass Petromyzontia 



Class PISCES 



1(2) Fishes with a cartilaginous skeleton and exposed gill 

 shts; marine forms. (Jordan, 14.) 



Subclass Elasmobranchii 



2(1) Fishes with a skeleton more or less bony; gill slits con- 

 cealed under an operculum; marine and fresh water. 



Subclass Teleostomi, p. 49 



