Reptiles and Amphibians of Illinois. 241 



Ozothem odorattt, Agassiz, L., Contr. Nat. Hist. U. S., 1857, 1., p. 



425;II., pi. 4, fig. 1 0. 

 AromocheJy.s odonitus, Davis and Ilice. Bull. 111. State Lab. Nat. 



Hist., I., No. .'), 1883, p. 53; Bull. Chicago Acad. Sci., 1883. 



Shell elongate, convex, widest posteriorly, smooth or with 

 an indistinct vertebral ridge in adults, distinctly keeled in 

 young. Nuchal plate small, elongate, and widest behind in 

 adults. First dorsal about half as wide behind as in front; the 

 three following dorsals hexagonal; last dorsal about half as 

 wide before as behind. Costals very large, covering the greater 

 portion of the carapace. Marginals, excepting one on each 

 side of the two caudals, narrow and elongate; the two mar- 

 ginals next the caudals equal to the caudals in size and about 

 twice the width of the other marginals. Plastron small, 

 rounded anteriorly, emarginate posteriorly. A single small 

 gular; postgulars small; pectorals large, and not specially nar- 

 rowed towards the middle line. Axillaries and inguinals meet- 

 ing and with the wings of the large abdominal plates forming 

 the bridge between the plastron and carapace. Head large; 

 snout conical; jaws very strong. Two to four gular tentacles; 

 two more widely separated ones on the throat and with numer- 

 ous small tuberculiform tentacles in series on the skin of the 

 neck. Anterior feet with about three transverse scales on their 

 anterior surface and with a few small ones on the palms; pos- 

 terior feet with transverse scutes on the heel. Digits 5-4, claws 

 sharp and curved. Skin of legs and tail with numerous papillee. 



Color of shell brownish black above and below in adults, 

 more or less yellowish beneath in young. Head greenish olive 

 or black with several stripes of yellow. A narrow stripe ex- 

 tends from the tip of the snout to the upper part of the eye 

 and is continued behind the eye by a stripe which terminates 

 abruptly in a spot on the side of the head. Another stripe of 

 the same color extends from beneath the nostril, where it meets 

 its fellow of the opposite side, backward beneath the eye, and 

 continues along the neck. There is a short stripe on each side 

 of the lower jaw which may continue posteriorly on the skin 

 of the neck. Other stripes are formed by the approximation 

 of the light-colored tentacles. Very young examples have a 

 distinct pale spot on the under side of each marginal plate, 



