AMPHIBIANS AND REPTILES. 39 
c. Sole with a single distinct tubercle. 
d. A dorsal groove; blackish above, with a series of yellow spots 
on each side. PUNCTATUM 
dd. No dorsal groove; lead-colored with inferior or lateral series, 
and usually a superior series of small irregular yellowish- 
gray spots. CONSPERSUM 
cc. Sole with 2 distinct tubercles; dark bar on side of neck. BICOLOR 
aa. Costal grooves usually 12. 
e. Sole with 2 distinct tubercles; brown, with yellow spots 
varying. 3 TIGRINUM 
ee. One or no tubercles on sole; leaden to brown, and pale 
spotted or not laterally. JEFFERSONIANUM 
Ambystoma opacum (Gravenhorst). 
PLATE 2. 
Blotched Salamander. Ambystoma opacum (Gravenhorst). 
Blotched Salamander. Marbled Salamander. 
Head 544; depth 914; width of head 1% in its length from 
snout to gular fold; length of mouth, or gape, 17g; interorbital 
space, measured from eye-sockets, 324; width of mouth 1%; 
snout 3%; fore limb about 1; hind limb 5% in total length of 
body; tail 13% in rest of body. Body thick, cylindrical, with 
swollen appearance. Surface all rounded, smooth and convex. 
Trunk nearly cylindrical, though with depressed appearance. No 
dorsal furrow. Costal grooves 11, including inguinal. Pelvic 
