I40 VERTEBRATE ANIMALS OF THE UNITED STATES 



parasphenoid broad: about species in the United States. These 

 salamanders can float in water without swimming movements, because 

 of their lungs. A . mexicaniim Shaw, the axylotl, which lives in a lake 

 near Mexico City, becomes sexually mature and breeds as a larva, 

 never transforming. It retains its gills and never leaves the water. 



Key to the United States Species of Ambystoma 

 ai Species east of the Rockies. 



bi Costal grooves lo to 12; vomerine teeth in i, 3 or 4 patches, 

 running across the mouth behind the nares (Fig. 70). 

 Ci Two plantar tubercles (Fig. 69) present. 



di Costal grooves 10 A. talpoideum. 



do Costal grooves 12 A. tigrinum. 



C2 One plantar tubercle present or none, 

 di Costal grooves 1 1 . 



ei Body with black and white bars A. opacum. 



e2 Body black with 2 rows of yellow spots A. maculatum. 



d2 Costal grooves 12; toes very long A. jeffersonianum. 



hi Costal grooves 14; teeth in 2 patches (Fig. 71). 

 Ci Definite color markings in form of cross bars. 



di Body black with narrow white cross lines A. cingulakim. 



d2 Body dark brown with broad yellow cross bars A. annulatum. 



C2 Black with whitish dots A. texanum. 



a2 Species in the Rockies and far-west. 



bi Four phalanges in the fourth toe of hind foot. 



ci Body mottled with black and yellow; no dorsal stripe. .A. tigrinum. 



C2 A light dorsal stripe present .4 . macrodactylum. 



b2 Three phalanges in the fourth toe of hind foot .4 . gracile. 



A. talpoideum (Holbrook). Mole salamander. Body short, stout, 

 depressed, gray or dark brown in color dotted with gray; head very 

 broad; length 90 mm.; tail 37 mm.; costal grooves 10; vomerine teeth 

 in 3 patches: southern States from North Carolina 

 y 'NyS^ to Louisiana and up the Mississippi Valley to 



Illinois. 

 — — C3M A. opacum (Gravenhorst). Marbled salaman- 



Pj^ g ^^^^ ^^ der (Fig. 67). Body thick, cylindrical, black above 



mouth of Ambystoma with about 14 grayish bars which may be confluent; 



opacum, showing vo- , , i .1 " ^ -i o 



merine teeth (from costal groovcs II ; length 95 mm.; tail 38 mm.; 

 Cope). plantar tubercles indistinct; vomerine teeth in 3 



patches: eastern States from central Massachusetts and New York to 

 Florida; westward to Missouri and Texas; in relatively dry and often 

 sandy locations, under stones and logs. 



A. maculatum (Shaw) {A. punctatum L.). Spotted salamander 

 (Fig. 68). Body stout; color black above, with a series of round yellow 



