Hurter — Herpetology of Missouri. 125 



season, wliich is the only time when it croaks. It is never 

 found in the water during the remainder of the season. 

 It is not often seen, but occasionally occurs in large num- 

 bers. They are said to be very skillful in hiding, and the 

 close resemblance of their colors to the dead leaves and 

 grass surrounding them renders it very difficult to find 

 them. Prof. S. F. Baird was the first to observe that the 

 tadpoles of this frog are carnivorous. (Hay.) 



Family Engystomatidae. 



No parotoids. Tympanum concealed. Fingers and toes not expanded 

 at their tips, the former without, the latter with or without, webs. No 

 teeth. Hearing apparatus fully developed. Prefrontals fully developed, 

 in contact with each other, and with the parietofrontals. No overlapp- 

 ing sternal cartilages. Clavicles and precoracoids sometimes wanting. 

 Transverse processes of sacrum dilated. 



It is represented in North America by the single genus 

 Engystoma. (Garman.) 



Genus engystoma. 



Head small, pointed, continuous with the body; mouth-cleft small; 

 tongue free behind, elliptical, entire. Limbs stout and rather short. 

 Eustachian ossicle very small. Males with an internal, subgular vocal 

 sac. (Garman.) 



35. Engystoma caeolinense Holbrook. Nebulous Toad. 

 Carolina Toad. 



Engystoma olivaceum. 



Description.- — Head short, pointed; body thick, nearly oval; skin 

 smooth. A fold across the head behind the eyes, which, however, is 

 often wanting in alcoholic specimens. Toes quite free with blunt tips 

 and distinct subarticular tubercles; a very small inner metatarsal tuber- 

 cle. With the hind limb carried forward along the body, the tibio- 

 tarsal articulation reaches the shoulder in the female, and a little be- 

 yond in the male. 



Color. — Color above olive-brown or gray, marked and spotted with 

 dusky; below pale yellowish, closely marbled with purplish, but more 

 yellowish posteriorly on the abdomen and under side of the femora. 

 Two wide, poorly defined pale bands begin at the fold of the skin be- 

 hind the eyes and pass backward and slightly downward to the insertion 



