NATURAL SCIENCES OF PHILADELPHIA. 215 



those of the last named genus, by the splitting away of the outer parapet of the 

 dentary bone. As no traces of alveoli have been thus rendered visible, I 

 suspect the dentition to have been pleurodont, as in existing Batrachia. 



No external surfiice of the mandible remains, but there are no impressions of 

 sculpture on the matrix. A" little external face of the premaxillary displays 

 none. 



Measurements. 



Lines. 



Preserved length of ramus (imperfect) 11. 



Depth at last tooth 2. 



Length of exposed tooth 1-7 



" dentary 75 



Depth at coronold 35 



" at first tooth 1-3 



SAUROPLEURA Cope. 



Neural and haemal elements of the caudal vertebrte elongate, distally dilated 

 and grooved, attached by contracted bases. Ventral aspect defended by a 

 series of oblique dermal ribs on each side, which meet anteriorly on the median 

 line. Limbs distinctly developed. Ribs long, well developed. Scales none. 



No dermal bones have been discovered, nor are any portions of the cranium 

 known. 



This genus is allied to the Urocordylus of Huxley, recently discovered in the 

 coal measures in Leinster, Ireland. It differs only in the presence of elongate 

 lizard-lilie ribs (whence the name), and in the absence of '• oat-shaped scales" 

 of the upper surfaces. 



It is a matter of much interest in American paleontology that this remark- 

 able type should be found to occur in our coal measures. It was first announced 

 by Dr. Newberry at the meeting of the American Association for the advance- 

 ment of Science for 1867 (see Proceedings, p. 144), as a supposed Urocordylus, 

 occurring with Ophiderpeton. He mentioned at the same time the discovery 

 of the ganoid Dinichthys Nevvb. 



The forms discovered by Dr. Newberry have an interesting relation to those 

 of Ireland, such as types of the present period frequently present. 



The genera may be thus parallelized ; where no representation exists, we 

 may look forward to a future discovery to supply the present want : 

 Ceraterpeton Huxl., represented by 



Urocordylus Huxl., " " Sauropleura Cope. 



Lepterpeton Huxl., " " 



Dolichosoma Huxl., " " Molgophis Cope. 



Ophiderpeton Huxl., " " Oestocephalus Cope. 



Brachydectes Cope. 



^ Herpetocephalus Huxl., ? ? Dendrerpeton Ow. 



Of the American genera, Sauropleura and Oestocephalus exhibit the peculiar 

 ventral dermal armature of Urocordylus and Ophiderpeton, while Molgophis 

 does not possess it, nor Dendrerpeton, if our species truly belongs there. 



The museum of Columbia College, New Vork, contains portions of two spe- 

 cies of Sauropleura, but both unfortunately represented by portions only of the 

 vertebral column. These are, though closely resembling the species described 

 by Prof. Huxley, sufficient to demonstrate marked generic distinction. This is 

 further established by the remains of the trunk of a third, and larger species, 

 whose relationships can be shown to lie within this genus. This individual 

 has been spread over a surface of the coal slate, exhibiting ventral armature, 

 dorsal region with ribs, and anteriof and posterior limbs. Of skull and caudal 

 vertebrae nothing remains. 



The dermal riblets are arranged as in Urocordylus, i. e., in parallel lines di- 

 rected obliquely forwards and continuous on the median line, lorming there a 



1868.] 



