THE BATRACUIA OF NORTH AMERICA. 99 



forameu in the base of the otoglossal cartilage. Wliere the latter is 

 fissured tbe crest appears to be clecurved througU it, as in C. paroticus, 

 PL 25, Fig. G. 



Tbe species of tbis geuiis are distributed as follows: 



AuSTRORiPARiAN Eegion. — C. microstomus and C. cingulatus. 



Pacific Region. — C. paroticus^ C. deoorticatus, (J. aternmus, and G. 

 tenebrosus. 



The (7. microstomus is not common in tbe eastern part of tbe Aus- 

 tioriparian region, but is cbiefly found in the Mississipi)i Valley and 

 Texas. Tbe Pacific species are all uortbern, none being yet known 

 from tbe middle and soutbern parts of California. 



Tbe species of Chondrotus are cbaracterized as follows : 



1. Vomeropalatiue tootli series estemliag exterior to the liuo of tlio iuterual nares; 

 lingual plicte radiating from behind ; parotoids not distinct. 

 a. Canthua rostralis distinct; tail shorter than head and body. 



Muzzle elongate, flat, produced beyond nostrils ; vomeropalatiue teeth in 

 two rather short series, which present an open angle backwards; brown, 



marbled with darker brown spots C. tenehrosits. 



II. Series of teeth extending to external fissure of inner nares ; lingual plicte radiat- 

 ing from behind ; parotoid glands forming a distinct ovoid mass. 

 a. Teeth in three series (no cauthus rostralis or plantar tubercles); fourth toe 

 with three phalanges. 

 Muzzle not produced ; median series of teeth forming an open angle forwards ; 

 width of head 4.5 to groin ; legs stout ; toes long ; tail longer than body ; 

 uniform brown C. paroUcus. 



III. Series of teeth not extending beyond inner line of nares; lingual plicaj radiat- 



ing from behind; no distinct parotoid mass (species large). 

 a. Twelve costal folds; no plantar tubercles ; fourth toe with three phalanges. 

 Vomerine teeth in one transverse series behind jiosterior line of ehoanfe ; tail 

 nearly as long as head and body ; muzzle very obtuse ; nostrils terminal ; 



light brown, with reticulations of dark brown C. decorticatus. 



Vomerine teeth in two sigmoids, which converge and join anterior to choan;u ; 

 tail only as long as body ; muzzle flat, produced beyond nostrils; uniform 



black C. aterrlmus. 



aa. Fourteen costal folds; fourth toe with four phalanges. 



Teetk arched between inner nares; head one-fourth to groin (in small speci- 

 mens'] ; eye one-half width between cauthus; muzzle broad; outer nearer 

 together than inner nares; brown, with a series of lighter spots on upper 

 part of sides, below yellowish; muzzle and tail marbled with the same. 



C. texanus. 



IV. Series of teeth not extending beyond inner margin of nares ; lingual plicae radi- 



ating from a median longitudinal furrow of the tongue ; no distinct paro- 

 toid mass (species small). 

 a. Two series of teeth; no canthus rostralis (fourth too with four phalanges). 

 j3. Tail compressed, equal to the body. 



Mandible shorter than muzzle; head elongate, width between eyes behind 

 equal from same to nares; width of head G. 5 times in length to groin ; 

 limbs longer, separated when appressed, by two intercostal spaces ; black, 

 with numerous narrow gray anuuli on bodj^ and tail... C. cingulatus. 



Mandible longer than muzzle; head short, broad; width between eyes behind 

 equal from same to end muzzle ; body stouter; width of head 6.5 to 7 

 times in length to groin ; limbs short, separated by six costal spaces; lead- 

 oolored, with a few gray shades below - C. microstomus. 



