220 PROCEEDINGS OF THE. ACADEMY OP 



ternal face to near the tip, which is probably owing to pressure, and a partial 

 crushing. Tlie points of the larger teeth are rather abruptly acute, and turned 

 abruptly backwards. A portion of tlieir increased length ('25) is to be attrib- 

 uted to the splitting oif of the external dentary margin, and the exposure of 

 the roots. No alveoli are shown, and the dentition is probably pleurodont, 

 with anchylosis of expanded base as in true Labyrinthodonts. 



MOLGOPHIS Cope. 



This genus is established on remains represented by three specimens, which 

 are two series of dorsal vertebra^ with ribs, and a series of caudals. One of 

 the dorsal series embraces sixteen vertebrae, the other fourteen ; the caudal 

 series, twenty-two. 



From its serpentine form this genus may be compared with the Dolichosoma 

 of Huxley, though a close relation does not exist between them. In the Irish 

 genus the series of caudal vertebrse is quite sliort, and the ribs are short and 

 but little curved. In Molgophis the tail has been like that of an elongate ser- 

 pent, and the ribs are as well developed as those of many reptiles. 



Though no limbs or arches can be certainly found, a rather quadrate, paral- 

 lelogrammic piece, about as long as the diameter of a vertebra, may be ^ 

 femur. This is, however, very doubtful. 



The characters of the genus are, a long serpentine body, without dermal 

 armature, so far as discoverable ; the vertebrfe large and broad, with very 

 prominent zygapophyses and moderate neural spine, those of the caudals with- 

 out narrowed bases (and grooved or serrate edges, most probably). ? Limbs 

 and cranium unknown. 



This genus differs from Urocordylus in i(s caudal vertebrae, and from Ophi- 

 derpeton in its dorsals; the latter, in their zygapophyses projecting laterally, 

 resemble those of Amphiuma. It differs from Sauropleura in the absence of 

 ventral dermal bands and in the longer body, without indication of limbs. The 

 size of the vertebrae would indicate a body of the size of a rattlesnake, (C. 

 h r r i d a), and therefore too large for the species named Brachydectes n e w- 

 b er r y i. 



The ribs are long, and though the head is not bifurcate, there appear to be 

 both tubercle and head on the dilated extremity. They show themselves, where 

 crushed, to have had a large median vacuity. 



Molgophis macrurus Cope. 



The neural arches, viewed from above, have a posterior V- shaped outline, 

 from the fact that the broad zygapophyses meet on the median line, and spread 

 out distally over the broad anterior ones adjoining. The latter appear to be 

 somewhat concave, and to border the former exteriorly as well as inferiorlj'. 

 The base of the neural spine extends to the posterior emargination, but not 

 quite to the anterior. The breadth of the dorsal vertebra above is equal from 

 the emargination behind to the anterior margin of the anterior zygapophyses. 



The caudal series must have been very long, as there is very little diminu- 

 tion in the size of the vertebrse throughout the series preserved. They present 

 much the same form as the dorsals, but are more contracted medially, and the 

 zygapophyses have a more transverse direction. There may indeed be a dia- 

 pophysial element beneath these, but tlie two cannot be distinguished if so. 

 They are connected by longitudinal impressions indicating the existence of the 

 tendinous bands in the longitudinal muscles seen in Amphiuma, or the osseous 

 spicules in the same situation in birds. The neural spines, indicated by their 

 narrow bases, occupied the lengths of the neural arch, and remind one of 

 Amphiuma. 



The ribs are long for a Batrachian, but shorter than in a reptile. They are 

 well curved, chiefly near the proximal extremity. The longest I can find, 

 measured by a chord, equals two vertebrai and two-fifths. Three vertebrae 



[Sept. 



