SUPPLEMENT TO THE EXTINCT BATRACHIA 



wards beneath the (?) post-frontal. These look like an anteriorly directed quadrate with articular bone, such as are 

 seen in larvas and some adults of existing batracLians. These determinations will require confirmation from addi- 

 tional material. In the meanwhile it is evident that the present specimen cannot be referred to any of the species 



herein described. 



3Ieasurements. . . . M. 



Total length of specimen, 0-0650 



" "a rib, ' .0050 



" " parietal and post-frontal bones, .0085 



Width of head at (?) quadrate, .0080 



Length of a vertebra, .0020 



Depth " " .0025 



This animal is dedicated to Cbas. M. Wheatley, A. M., of Plicenixville, Pennsylvania, one of the original in- 

 vestigators of the deposit in which it occurs. 



PTYOXIUS, Cope. 



Genus novum. Saurojilcura part. Cope, Proceed. Acad. Nat. Sci., Philadelphia, 18G8, 217. O'estocepTiahis 

 part. Cope, Ti-ansac. Amer. Philos. Soc, XIV, p. 20. 



Form elongate, with long- tail and lanceolate craninm. Limbs weak, a posterior 

 pair only discovered. Three pectoral shields present ; abdomen protected by packed 

 osseous rods which are arranged en chevron, the angle directed forwards. I^eiiral and 

 haemal spines of caudal vertebra? expanded and fan-like. Ribs well developed. 



This genus is the most al^undantly represented by species and individuals, among 

 those found at Linton. These are almost snake-like in their proportions, and vary in 

 length from three to ten inches. The muzzles of the known species are acuminate, 

 and the upper surfaces of the cranium in the three species, where it is preserved, are 

 sculptured by rather distant crests and tubercles. 1 he squamosal is evidently more 

 expanded than in recent Batracliia either of the tailless or tailed orders- In P. pecti- 

 natus and P. vincliellianus it is a broad plate concealing the quadrate, and apparently 

 readily separated from it, as it is loose in some of the specimens. This is an inter- 

 esting point, as the homology of the squamosal with the preoperculum of the fishes 

 has been proposed by Pai-ker and the writer,'" and the view is confirmed by the re- 

 semblance of the former to aii opei'culum in these the most fish-like of the Batracliia. 

 The teeth are numerous, small, and some of them apparently simple ; others appear 

 to be gi'ooved. In a cranium (]S^o. 140) perhaps of P. pectinatus, they extend to the 

 tip of the slender jaws, are rather stout, acute, and evidently marked with a few 

 strong grooves on the shank. The form of the head is a curious miniature of 

 Ichthyosaurus. 



Remains of limbs have only l^een observed in the position of the posterior pair, 

 and that in several individuals, 



*See Proceed. Amer. Asso. Adv. Sci., Vol. XIV., p. 222. 



