01 



COMPSEMYS, Leidy. 



This genus presents the characters of Etnys in its \v(!ll-dev(!loped 

 niarifinal bones, united to the costals hy suture. The surfaces ot" the 

 carapace possess a dense layer, wliich is sculptured in two of the known 

 species. One of these, the C. rictus, Leidy, has been found to have had a 

 wide range in the West (hiring th(! P^ort Union epoch; while a second has 

 been lound in corresponding strata near the northern boundary of Dakota. 



CoMPSEMYS OGMIUS, Cope. 



Ki'presented in the collecliuns of the British American Boundary Coui- 

 Miissi(ui by portions of the carapace and plastron. These are massive, and indi- 

 cate a s[)ecies of large size. As in other species of the genus, the external 

 surface is a dense layer of cement or allied substance, which is sculptured 

 \\itli shallow pits. 



A portion of the costal bone is concave, and increases rapidly in thickness 

 in one direction. The suture is coarse, but neither gomphosial nor squamosal. 

 A portion of the plastron is thinner, not curved, and displays a very coarse 

 median suture, in part squamosal in character. The sculpture consists of shallow 

 pits, not wider than the low, smooth ridges which separate them. There are 

 deep superticinl grooves, marking the boundaries of dermal areas; a feature in 

 which this tortoise differs much from the P. coalescens, and resembles the 

 species of Compaemys. Should nuirginal lioues be found to exist in the F. 

 ogm'ms, its rci'crence to that genus will l)e further established. 



From six miles west of first branch of Milk River, near latitude 49°. 



ADOCUS, Cope. 



Pi-oceeiliiigs of tbe Academy <j( Natural Sciences, Philadelpbia, 1868, p. 235; I'roceediugs of tUo 

 American Philosopliical Society, 1870, November. 



This genus possesses a large intergular plate. This I have verified on A. 

 heutus and A. si/ntheticus. Having also perfect xiphisternal bones of these two 

 species, I can show that there is no sutural attachment lor the pelvic bones. 

 Tiie co-existence of these two characters has been hitherto found to be uni- 

 versal, and the present deviation from it is a point of much interest. Instead 

 of sutural surfaces, there is an obtuse ridge corresponding to the pubis, and a 

 knob answering to the extremity of the ischium, both more prominent than is 

 usual ill genera of Kmydidm. 



