438 



AMERICAN TESTUDINATA. 



Part II. 



ish green to reddish brown, plain, or dotted or striped concentrically. I am 

 indebted to Prof. Baird for a large series of specimens from the Middle States; Dr. 

 Nott has sent me others from the Gulf States. Dr. Holbrook's figure (PI. 12) rep- 

 resents a broad-headed variety; DeKay's, (Zoology of New York, PI. 3, fig. 5,) one 

 with a pointed head.^ The young are represented PI. 1, fig. 10-12 ; the eggs, PI. 

 7a, fig. 11-14. 



V. Chrysemys, Gray. Although J. E. Gray considers these Turtles only as a 

 sub-genus of Emys, I am satisfied that they belong to a distinct genus, the rep- 

 resentatives of which are closely allied to the other Nectemyds, and not to the 

 Clemmyds, as Wagler supposed. The large web of their feet and the broad hori- 

 zontal alveolar surface of the upper jaw show this distinctly, even though the 

 horny sheath that covers its edge be narrow. They die in a few days when kept 

 out of the water, while the Clemmyds are much more terrestrial, and may be kept 

 for months on dry ground during the hottest days of the summer. This is the case, 

 at least, with Glyptemys insculpta. The most prominent generic character con- 

 sists in a notch in front of the horny sheath of the upper jaw, on each side of 

 which the edge of the sheath projects more or less to form lateral teeth, that 

 are close together. The young are not keeled^ at all, and are flatter than 

 those of the other genera. The colors are very constant, and afford good sjiecific 

 characters.^ 



Chrysemys picta, Graij} This species may be at once distinguished from the 

 other species of the same genus by the form of the middle row of scales upon 

 the back, and the manner in which the costal scales^ of the carapace meet those 

 of the vertebral row, and also by a broad, yellow band, limited by a black line, 

 which extends along their anterior margin. The ground color is dark, grayish 

 brown ; the margin has intensely blood-red blotches. The scales of the median 

 row have their lateral angle higher up, and the upper margin of the lateral 

 scales nearly on a line with the upper margin of the median scales, while in 

 all the other species the median scales are more regularly hexagonal, and the 



' J. E. Gray's Emys macrocephalus, Cat. Brit. 

 Mus. 1844, p. 2G, is a large-beaded variety of this 

 species. 



^ The absence of a keel in the young, and the small 

 size of the adult, seem to indicate that this genus 

 stands highest in its sub-family. 



' The only variations that I have noticed corre- 

 spond to the changes which take place with age ; there 

 is, though very rarely, some difference in the extent 

 of the lyriform figure upon the sternum. 



^ This is the well-known Emys picta of most 



modern berpetologists, the Testudo picta of Hermann 

 and Schneider ; Testudo cinerea, Broivn, Emys cine- 

 rea, Schw., is the young. Seba already mentions it 

 as Testudo ex Nova Hispania. It also appears as 

 Terrapene picta in Prince Canino's works. AVagler 

 calls it Clemmys picta. 



^ Occasional anomalies are observed in the form 

 of the scales. Prof. S. S. Haldeman has sent me one 

 specimen In which one of the costal scales and the pos- 

 terior median scales of the back are divided ; and an- 

 other in which there is one additional costal scale. 



