Reptiles and Amphibians of Illinois. 223 



ence in the margias of the carapace and in the form and width 

 of the plastron, but the latter are characters which vary in the 

 same species with age. 



Plastron black centrally, with rays of this color extending out 

 along sutures, front edge deeply denticulate C. belli. 



Plastron reddish orange or yellow. Dorsal and costal plates 

 alternating C. marginata. 



Plastron reddish orange or yellow. Dorsal and costal plates in 

 transverse rows of three C. picta. 



Chrysemys belli, Gray. 



Emys belli, Gray, Synopsis Reptilium, 1831, p. 12.— Dum. et Bibr., 

 Erp. Gen., 1835, II., p. 502. 



Chrysemys hellii, Agassiz, L., Contr. Xat. Hist. U. S., 1857, 1., p. 

 439.— True, Yarrow's Check List N. A. Rept. and Batr., 

 1882.— Garman, S., List N. A. Rept. and Batr., 1884. 



Shell depressed; no keel; uniformly convex above; mar- 

 gins nearly continuous; a very slight notch behind; nuchal 

 plate elongated, narrowed forwards, notched in front. Plas- 

 tron truncate behind, with no decided angles; outer angles of 

 gulars protuberant. Head below medium in size; jaws weak; 

 tympanum evident. Feet medium, fingers and toes fully 

 webbed; nails strong and sharp. 



Length of carapace, 4.25; width, 3.38; depth of shell, 

 about 1.50. 



Dull black above, with a greenish cast, with obscure yel- 

 lowish lines following sutures below the dorsal and costal 

 plates. Marginals above with about three transverse lines, the 

 median of which reaches the inner margin of the plate, and 

 sometimes joins a yellow band along the outer margin; mar- 

 ginals beneath with a broad median band which may, within, 

 join the stripes of adjacent plates. Plastron red, with the 

 central region occupied by a large blackish lyriform blotch 

 which is marbled with pale yellow and sends rays out along the 

 sutures. Sometimes also with a pair of isolated blackish spots, 

 one near the outer edge of each pectoral plate. Head and legs 

 striped with red as in C. marginata. Noticeable lines on the 

 head are as follows: a slender median stripe extending from the 

 snout to a point nearly opposite the anterior edge of the tympa- 



