Chap. III. GENERA OF TRIONYCHID^. 405 



AlU'gliany River, in Western Pennsylvania, from Professor Baird. It was not 

 known in the State of New York before the completion of the Erie Canal; but 

 since, it has been caught in the Mohawk and in the Hudson Rivers, near Albany 

 (DeKay). Professor Rich. Owen has sent me some from the Wabash, near New 

 Harmony, in wliirh place LeSueur first observed this species. It is abundant 

 in Lakes Ontario and Erie, in the streams that flow into these lakes, (Say and 

 LeConte,) and in all the streams of Ohio (Kirtland). I am indebted for speci- 

 mens from the Ohio to Mr. Jos. Clarke, of Cincinnati ; from Northern Indiana to 

 Mr. Franklin Hill, of Delphi; from Michigan, to Dr. A. Sager and Professor 

 Alex. Winchell, of Ann-Arbor; from Illinois, to Mr. J. H. McChesney; from 

 Iowa, to Dr. J. Ranch ; from the Osage River, in INIissouri, to Mr. G. Stolley ; 

 and from Fort Union, on the Upper Mis.soui'i, to the Smithsonian Institution. 

 It is frequently found in the smaller streams that discharge into the Missouri 

 (Say). The occurrence of this species so far north contrasts strangely with the 

 opinion, prevailing among herpetologists, that the representatives of this fomily 

 are inhabitants of the large rivers of the tropics.^ 



AsPiDoxECTES ASPER, Aff. I havo for a long time known only an imperfect 

 skeleton of this species, belonging to the Smithsonian Institution, and prepared 

 from a specimen forwarded by Professor B. L. C. Wailes, of Washington, INIissis- 

 sippi. Afterwards I obtiiined, through the agency of Dr. L. Harper, a stuffed 

 specimen belonging to the Museum of the University of Oxford,^ that had been 

 collected during the geological survey of Mississippi, under the superintendence 

 of Professor Wailes. Lately I have received a number of living specimens, 

 through the kindness of Mr. Winthrop Sargent of Natchez, which confirm the 

 opinion I had formed, from the scanty materials at first at my command, that 

 there exists, in the South-Western States, a distinct species of Aspidonectes, which 

 might easily be mistaken for Asp. spinifer, and even be confounded with Plat}-- 

 peltis ferox.^ 



Aspidonectes asper is at once distinguished from all the other species of this 



' C'omi). JJuin. and I'.ihr. Erpi't geiiur. Vol. 2, p. of very great iniportaiu-c to mo in fixing tlie gco- 

 449, where it is stated that all tin; species, the origin graphical range of many species, which before were 

 of which is known, inhabit the rivers and lakes of the not known to occur in the lower course of the Mis- 

 wannest parts of the globe, among wliicli. it is true, sissippi. 

 they mention the Oiiio. ' I have no doubt that such a confusion generally 



^ Upon application of Dr. Harper, the trustees of prevails, as no zoologist has thus far alluded to the 



the University at Oxford very liberally consented to presence of two rci)resentatives of this family in the 



forw.-ird to me for examiiialiiMi all the specimens of Southern States, and the very si)ccinu'n of the Mu- 



Testudinatu collected during tlie geological survey of seum of Oxford, alluded to above, bears the name of 



the State of Mississippi. These specimens have been Trionyx ferox. 



