218 PROCEEDINGS OF THE ACADEMY OP 



similar ala exists on the posterior margin of the neural spine, which extends 

 for a shorter distance above the base, and is narrower than the anterior. Each 

 spine presents a median groove on its surface, which extends halfway to the 

 base or further ; on each side of this are some three other grooves, 

 which extend but a short distance ; surface otherwise smooth. The ends of 

 the grooves slightly notch tlie truncated end of the spine. 



The hremal spines are on the posterior portions of the centra, and in con- 

 tact with the anterior part of the basis of those succeeding. They are without 

 the dilatations of the neural spines, and are directed rather more obliquely 

 backwards. They are similarly grooved, though without that so distinctly 

 median, seen -in the neural series. , 



Both neural and h;emal spines become larger towards the posterior part of 

 the vertebral column. There appear to be no zygapophyses nor diapophyses, 

 nor rudiments of ribs. The centra are rather stout, and somewhat constricted 

 medially. There are no traces of dermal armature of any kind. 



Measurements. 



Lines. 



Length of a posterior centrum 1"2 



Depth " " " 1- 



Length neural spine of adjoining vertebra 4-4 



Basal width 1'4 



Median width , "9 



Distal width 1-1 



Length of a more anterior neural spine 4-3 



Distal width " " " " 1-5 



" anterior haemal spine 4 



" width " " , 1-4 



From the Coal Measures, the Western Pennsylvania and Ohio Bituminous 

 Basin, at Linton, Columbiana Co., Ohio, near the Ohio River. Prof. J. S. 

 Newberry. 



CESTOCEPHALUS Cope. 



This genus is known from a single species as yet. As before remarked, it 

 represents in many respects the Ophiderpeton of Huxley, and has been alluded 

 to by Dr. Newberry as the same. It, however, differs markedly in the narrow 

 lanceolate form of the head, with probable accompanying peculiarities of de- 

 tail, and in the presence of limbs, which have not been found in the Irish 

 genus. The form of the head is somewhat nearer that of Lepterpeton Huxl., 

 but the limbs of the American genus have as yet been seen as one pair only, 

 and very small, while in Lepterpeton there are two pairs, which are large. 

 The general form of the body of Oestoccphalus is more snake-like. 



In more detail, we have an elongate lanceolate head with little or no sculp- 

 turing of the external surface of the bones. The angles of the mandibles are 

 much prolonged backwards as in Archegosaurus and frogs, and the well de- 

 veloped ribs commence but a short distance behind the head. The vertebrae 

 are slender, and furnished with well developed diapophyses. A pair of sym- 

 metrical bones, whose impressions are seen posterior to the occipital region, 

 look like ceratohyals or small scapulee, and one of them is continuous with 

 a second piece, which occupies the place of a humerus A third piece follows, 

 which is probably ulna ; no radius or manus is preserved. This then is a 

 rudimental fore limb, situate very close to the head. The skin has been occu- 

 pied by a great number of closely packed, curved, spine-shaped scales. They 

 have occupied the ventral integument passing from the median line of the belly 

 outwards and posteriorly, having acute tips which may have penetrated the 

 Bkin on each side ; whether such tegumentary spines protected the back can- 

 not now be determined. 



[Sept. 



