THE AISTOPODOUS MICROSAURIAN FAMILY PTYONIID^E. 143 



tured. The tail is relatively longer. Abdominal rods hair-like. Ribs distinct. Small 

 limbs are present in one specimen. 



MEASUREMENTS OF COPE'S TYPE OF PTYONIUS SERRULA. 



mm. mm. 



Length of specimen 95 Width of clavicle 1.5 



Length of portion of skull preserved 3 Length of vertebra I 



Length of mterclavicle 4.5 Width of vertebra from tip of neural spine to tip 



Width of interclavicle '. 2 of haemal spine 4 



Length of clavicle 4 



Another specimen (456 G, American Museum of Natural History) shows some 

 of the same characters. There is not the slightest basis for the support of- this spe- 

 cies, so far as I can observe. The ones mentioned by Cope are insufficient. It is in 

 all probability a mutant or variety of Ptyonius pectinatus. 



Genus (ESTOCEPHALUS Cope, 1868. 



COPE, Proc. Phila. Acad. Nat. Sci., 218, 1868. 

 COPE, Trans. Amer. Phil. Soc., xiv, 16. 

 COPE, Proc. Phila. Acad. Nat. Sci., 1868, 217. 

 COPE, Proc. Amer. Phil. Soc., 1871, 41. 

 COPE, Geol. Survey Ohio, n, pt. u, 380, 1875. 



Type : CEstocephalus remex Cope. 



Form slender and snake-like; caudal vertebrae with elongated, dilated, sculp- 

 tured neural and haemal spines. Cranium lanceolate. Teeth numerous, of nearly 

 equal size. No pectoral shields known; abdomen protected by very numerous 

 bristle-like rods, which converge forwards. A pair of weak posterior limbs; branchi- 

 hyal bones present. 



In the only well-preserved species the cranial bones exhibit no sculpture from 

 the parietal region forward. The genus is not very distinct from Ptyonius, but it 

 can not be united with that genus until more complete material is available. The 

 species of the genus share with Ceraterpeton, Urocordylus (334), and Ptyonius, as 

 well as Crossotelos (98), from the Permian of Oklahoma, the elongation, sculpture, 

 and expansion of the neural and haemal spines. There are but 2 species, which 

 Cope distinguishes by the following characters: 



I. Vertebrae elongate; fan-like caudal processes narrowed. Size large; mandibular teeth of unequal lengths, 



with the apices turned backward (Estocephalus remex 



II. Species only known from cranial bones with teeth. Teeth equal, erect, with acute conic apices, II in 



5 mm CEstocephalus rectidens 



CEstocephalus remex Cope. 



COPE, Proc. Phila. Acad. Nat. Sci., p. 217, 1868 (Sauro pleura remex). 



COPE, Proc. Phila. Acad. Nat. Sci., p. 218, 1868 ((Estocephalus amphiumianus). 



COPE, Trans. Amer. Phil. Soc., xiv, p. 17. 



COPE, Geol. Surv. Ohio, vol. II, pt. u, p. 381, pi. xxvii, fig. 5; pi. xxxi, fig. I ; pi. xxxii, fig. I ; pi. xxxiii, fig. 2; 



pi. xxxiv, fig. 4, 1875. 

 MOODIE, Proc. U. S. Nat. Mus., 37, p. 27, 1909. 



Type: Specimen undetermined. The following specimens are to be found: 

 Specimens of (Estocephalus remex Cope in the National Museum, Nos. 4511, 4460, 

 4478. There is one specimen of (Estocephalus remex in the University of Chicago. 

 Specimens of the species in the American Museum of Natural History: Nos. 121, 

 8322 G, 8694 G, no number, 8656 G, 8583 G, 8659 G, 19, 120, 8655 G, 8662 G, 

 8708 G, 8665 G, 112, 8663 G, 8581 G, 8658 G, 8660 G, 8700 G, 8469 G, 1102 G, 

 1152 G 142, 8381 G, and obverse, 21, 8664 G, 8672 G, 8592 G, 8684 G. 



Horizon and locality: Linton, Ohio, Coal Measures. 



