THE AISTOPODOUS MICROSAURIAN FAMILY PTYONIID^. I4I 



No traces of fore limbs have been detected in the numerous specimens, but ele- 

 ments of hind limbs are preserved. In one of these the femur is a small bone, 

 contracted at the middle. The form of the body is snake-like. 



There were probably from 75 to 100 vertebrae in a single animal. The form may 

 be well compared to the modern Amphiiima so far as appearances are concerned; 

 structurally they are widely separate. This species is one which is peculiarly char- 

 acteristic of the Linton fauna. 



Measurements of Ptyonius pectinatus Cope. 



Nos. 107 and 10Q4 G, American Museum. Measurements of a small jaw, No. S555 G, American 



Museum. 

 nim. _ mm. 



Length of specimen 137 Length of jaw 15 



Length of skull 26 Greatest width 1.5 



Posterior width of skull 8 Length of tooth I 



Interorbital width 3 Measurements of specimen No. 4458, U. S. National 



Diameter of orbit 1.5 Museum. 



Vertical expanse of vertebra 6 Length of specimen 65 



Width of neural fan 2 Length of skull 22 



Diameter of pedicel i Width of skull 6 



Ptyonius vinchellianus Cope. 



Cope, Proc. Am. Phil. Soc., p. 177, 1871. 



Cope, Geol. Surv. Ohio, n, pt. n, p. 376, pi. xxviii, fig. i, 1875. 



Type: Specimen in the American Museum of Natural History. 



Horizon and locality: Linton, Ohio, Coal Measures. 



The species is represented by the opposite halves of a single specimen, which 

 includes only the cranium and anterior half of the body. The fan-shaped neural 

 spines commence but a short distance behind the line of the pectoral shields. They 

 are low, with a few coarse ridges, the margin being entire. The abdominal rods are 

 delicate and hair-like. The interclavicle is oval, with a few radiating crests, which 

 originate at the center; in the areas behind there are a few scattered tubercles. 

 The clavicles are ridged near the margin. 



The cranium is lanceolate in form, and the bones of the dorsum are marked with 

 a few raised points and ridges. The species is about the size of Ptyonius pectinatus 

 Cope, and differs, apparently, from that species in the rather insignificant charac- 

 ter of a narrower interclavicle and in the ornamentation of the same. Dedicated to 

 Professor Alexander Winchell, of the University of Michigan. 



Measurements of Ptyonius vinchellianus Cope. 



mm. 



Length of cranium 20 



Width of same 8 



Length of interclavicle 4.2 



Ptyonius marshii Cope. 



Cope, Trans. Amer. Phil. Soc., .xiv, p. 24, 1869 (Colosleus marshii). 



Cope, Geol. Surv. Ohio, II, pt. 11, p. 375, pi. xxvii, fig. 6; pi. xxviii, fig. 3, 1875. 



Cope, Proc. Am. Phil. Soc., xii, p. 177, 1871. 



Type: Specimen No. 1157 G, American Museum of Natural History. 

 Horizon and locality: Linton, Ohio, Coal Measures. 



The head is elongate lanceolate. The upper surface of the frontal bones is 

 punctate-rugose in relief, with short radii toward the margin. The distal two- 



