PLETHODONTID.-E. OIL 179 



255. CHONDROTUS Cope, (xovdpos, cartilage ; ovs, ear.) 

 501. C. microstomus Cope. Blackish, usually with plumbeous 

 shades and specks ; head small, short, broad ; body slender ; skin 

 very smooth and slippery ; snout very short, the lower jaw project- 

 ing beyond it. Costal grooves 14. Ohio to Kansas and S. (piicpos, 

 small ; cra'/na, mouth.) 



FAMILY OIL PLBTHODONTID^l. 



Vertebrae amphiccelian ; carpus and tarsus cartilaginous ; para- 

 sphenoid with one or two laminae which are covered by a coarse 

 brush of teeth which look downwards on roof of mouth. The 

 species with cylindric tails rarely or never enter water. Genera 1 1 ; 

 species 35 ; chiefly North American. 



a. Tongue attached by a band running from its central or posterior pedicel to 



the anterior margin ; premaxillaries two, with fontanelle. 

 b. Toes 4-4 .............. HEMTOACTYTJTTM, 256. 



bb, Toes 4-5 ................ PLETHODON, 257. 



aa. Tongue free all around, attached by its central pedicel only; toes 4-5, all 



free. 

 c. Premaxillaries two, with fontanelle ..... GYEINOPHILUS, 258. 



cc. Premaxillary single, with fontanelle ..... SPELERPES, 259. 



256. HEMID A CTYLIUM Tschudi. (q/u-, half ; daKrvXos, toe.) 



502. H. scutatum (Schlegel). Brown above; snout yellow; 

 whitish below, with dots like ink spots ; body short ; tail slender ; 

 skin of back with depressions resembling scales. Costal grooves 

 13. L. 2. R. I. to 111., and S. 



257. PLETHODON Tschudi. (77X^09, crowd ; o6\ai/, tooth.) 



a. Costal groove 16 to 18 ; palatine teeth not extending outward beyond inner 

 nares. 



503. P. erythronotus (Green). Plumbeous above, often with a 

 broad brownish red dorsal band ; belly marbled ; body very slen- 

 der ; tail cylindric ; inner toes rudimentary. L. 3. E. U. S., 

 common under logs, etc. ; nocturnal in habit and very active. Var. 

 cinereus Green, found with the other, lacks the red dorsal band. 

 (epvQpos, red ; V>TOS, back.) 



aa. Costal grooves 14; palatine teeth extending outside of inner nares. 



504. P. glutinosus (Green), Black, usually with bluish-white 

 blotches and specks ; stout ; tail rounded ; inner toes well de- 

 veloped. L. 5 to 7. E. U. S., chiefly terrestrial. 



258. GYRINOPHILUS Cope. (yvpW, tadpole ; t 'Aos, lover.) 



505. G. porphyriticus (Green). Yellowish or purplish brown 



above, irregularly blotched with gray ; head broad ; tail rounded at 



