136 



VERTEBRATE ANIMALS OF THE UNITED STATES 



metamorphosis, except in Nee turns, Typ/ilomolge, Pseudohranchus and 

 Siren. In some of the Plethodontidce the greater part of the larval 

 stage is spent in the egg and the young are terrestrial from the time of 

 birth and without gills. The lower Caudata are aquatic animals 

 throughout Hfe, the higher ones are mostly terrestrial as adults, but 

 must still live in moist places. 



The 150 species of Caudata are grouped in 2 suborders and are found 

 mostly in the temperate parts of the northern hemisphere; about 99 

 species occur in North America and 69 species in the United States. 



On the Identification of Caudate Amphibia.— The descriptions 

 of salmanders in this book apply to adult animals. The most important 

 descriptive features are the shape and appearance of the body and its 



Fig. 64. Fig. 65. 



Fig. 64. — The naso-labial groove of Desmognathns fusciis, /, crescentic fold which closes 

 the nostril when the head is submerged; gr, naso-labial groove which drains the nostril 

 when the head emerges from the water; grl, labial groove; nl, orifices of glands {from 

 Whipple) . 



Fig. 65. — The ypsiloid cartilage of Triturus viridescens: I, pubis; y, ypsiloid cartilage; 

 the other letters refer to muscles {from Whipple). 



color, the length of the body in millimeters, including the tail, the length 

 of the tail, the number of costal grooves between the fore and hind 

 limbs, the number of digits, and the position of the teeth, especially 

 those of the vomers and parasphenoid. The naso-labial groove, a 

 glandular groove passing from the nostril to the lip (Fig. 64), and the 

 plantar tubercles, which are elevations on the palms and soles, are also 

 often important. Several features of the internal structure are impor- 

 tant in a full analysis of the various groups, although a knowledge of 

 them is not usually necessary for the identification of species; these are 

 the shape of the vertebrse, the form and condition of the cranial bones 

 and cartilages, the presence or absence of the lungs and of the cartilage 

 which may lie in the ventral body wall just anterior to the pubis and is 

 called the ypsiloid cartilage (Fig. 65). 



