228 Illinois State Laboratory of Natural History. 



in a small hole dug in the sand, and are then covered up and 

 left to hatch in the heat of the sun. 



PSEUDEMYS, Gray. 

 Gray, Cat. Shield Kept., 1855, p. 33. 



Carapace moderately depressed. Plastron rather large, im- 

 movably fixed to the carapace, with no transverse hinge, emar- 

 ginate before and behind. Wings of pectoral and abdominal 

 plates well developed. Axillary and inguinal plates rather 

 large and about equal in size. Alveolar surfaces of jaws rather 

 wide and with a median ridge parallel to their margins. Digits 

 5-4, moderately Jong, fully webbed. 



Ridges on alveolar surfaces of jaws smooth. Both jaws with 

 smooth edges. 



With a broad orange stripe on each side of head. Carapace 

 with yellow stripes P. elegans. 



Without orange stripe on head. Markings of head and neck 

 obscure. Carapace without yellow stripes . . P. troosti. 

 Ridges on alveolar surfaces of jaws tuberculate. 



Both jaws with smooth edges. Shell greatly de- 

 pressed P. hieroglyph ica. 



Lower jaw with serrated edge. Not greatly de- 

 pressed P. concinna. 



Pseudemys elegans, Max. 



Emys elegans. Max., Reise Nord-Amer., I., 1839, pp. 176, 213. 

 Trachenujs elegans, Agassiz, L., Contr. Nat. Ilist. U. S., 1857, 1., p. 



435. 

 Pseudemys elegans, Jordan, Man. Vert. N. U. S., 3d ed., 1880, p. 



1(55.— Davis and Rice, Bull. III. State Lab. Nat. Hist., I., No. 

 , 5, 1883, p. 56; Bull. Chicago Acad. Sci., 1883. 



Carapace moderately depressed, convex, with very slight 

 indications of a keel in small examples only, emarginate be- 

 tween the posterior marginal plates, making the edge obtusely 

 ■errate. Plastron emarginate before and behind. Anterior 

 lateral angles of the gulars slightly produced. Head of medi- 

 um size; upper jaw with a median emargination, lower jaw 

 ■with a corresponding median tooth. Digits 5-4. 



