404 AMERICAN TESTUDINATA. Part II. 



The only correct description I know of Aspidonectes spinifer is that of Le- 

 Sueur.^ All later writers have confounded it more or less with Platypeltis ferox, 

 until the two were finally considered as identical. Its chief specific characteristics 

 are not the spines along its anterior margin, whence the name is derived, — for 

 such spines exist more or less in all species of the genus Aspidonectes, — but the 

 blunt keel, which extends along the median line and slopes uniformly upon the 

 sides, a character by which it is easily distinguished from Aspidonectes nuchalis, 

 a species thus far overlooked, in which there is a marked depression on either 

 side of a similar keel along the median line. When young, Aspidonectes spinifer 

 (PI. 6, fig. 1 and 2) is dotted all over the back with small ocellated spots, which 

 increase with age, and then fade into irregular blotches upon a darker or lighter 

 yellowish brown ground. In early age, the margin has a narrow, light-colored 

 seam, separated from the darker disc by a black line, which fades and disappears 

 with age. The front part of the neck is mottled with yellow and black, and 

 so, also, is the lower surface of the feet. Besides the difference in the length 

 of the tail, the male differs from the female by a slightly oval form. The 

 spines along the front margin, and the tubercles which rise behind them and 

 upon the hind part of the carapace, are less prominent in the males than in 

 the females, exactly the reverse from Platypeltis ferox. The largest specimen I 

 have seen, measured fourteen inches from end to end of the carapace. The eggs, 

 (PI. 7, fig. 23,) for which I am indebted to Dr. Ranch and Mr. Franklin Hill, 

 are a little larger than those of Platypeltis ferox. Major LeConte questions 

 the propriety of the name ferox for the southern Trionyx, as he says they are 

 not more inclined to bite than most other species of Testudinata; but LeSueur 

 reports that he was severely bitten by Tr. spinifer, and I have myself experienced 

 the 230wer of its jaws. This apparent contradiction, as long as ferox and spinifer 

 were considered as the same species, may be owing to the generic differences of 

 these Turtles. Aspidonectes sj)inifer is common from Lake Champlain and the 

 western parts of the States of New York and Pennsylvania, through Ohio, Indi- 

 ana, Illinois, Missouri, Michigan, Wisconsin, and Iowa, to the head waters of the 

 Mississippi and Missouri, even to the very foot of the Rocky Mountains (Lewis 

 and Clark). It inhabits most of the tributaries of the Mississippi within the 

 State of Wisconsin (Dr. P. R. Hoy). I have received specimens from Lake 

 Champlain, through the kindness of the late Rev. Zadd. Thompson ; and from the 



^ In the Memoires du Museum d'Histoire natu- under tlie name of Trionyx ocellatus, what was, no 



relle, Vol. 15, p. 258, PI. 6, under tlie name of Trio- doubt, a young female. Wagler considers this species 



nyx spiniferus, which ought, however, to be written as synonymous with Platypeltis ferox. DeKay's Tri- 



spinifer. LeSueur describes as a variety of this siiecies, onyx ocellatus is Amyda mutica. 



'\ 



