Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/25

 AND AYES OF NORTH AMERICA. 21 series of caudal vertebne is quite short, and the ribs are short and but little curved. In Afolgophis the tail has been like that of an elongate serpent, and the ribs are as well developed as those of many reptiles. • Though no limbs or arches can be certainly found, a rather quadrate, parallelogrammie piece, about as long as the diameter of a vertebra, may he found. This is however yen doubtful. The characters of the genus are : a long serpentine body, without dermal armature, so far as discoverable ; the vertebras large and broad with very prominent zygapophyses and moderate neural spine, those of the sandals without narrowed bases (and gthoved or serrate edges. most probably). Limlis and cranium unktiown. This genus difkrs from Urocordylus ill its caudal vertebrae, and from Ophiderpeton in its dorsals: the latter in their zygapophyses projecting laterally resemble those of Amphi-It differs from (Estocephalus in the absence of ventral dermal bands and in the longer body, without indication of limbs. The size of the vertebral would indicate a body of the size of a rattlesnake, (Cr. horri►«.) and therefore too large for the species named Brachydectes newberryi. 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 a large median vacuity. MOLGOPHIS MACRURUS, Cope. The neural arches viewed from above have a posterior V-shaped outline, front the fact that the broad zygapo-physes 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 inferiorly. The base of the neural spine extends to the posterior emargivation, 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 zygapophysis. The caudal series must have been very long, as there is very little diminution in the size of the vertebrae through-out 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 diapophysial element beneath these, but the two cannot be distinguished if so. They are connected by longitudial impressions, indicating the existence of the tendinous bands in the longitudinal muscles seen in Amphiunua, or the osseous spicule* in the same situation in birds. The neural spines indicated by their narrow bases, occupied the length of the neural arch, and remind one of Amphiuma. The ribs are long for a Batrachiau, 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 vertebra and two-fifths. Three vertebr:e measured along the median line above equal eleven lines ; one of these is 3.6 Hues in width above : width of a ell posterior caudal 3 1. This animal has been like Amphiuma a snake-like liatrachian, but probably of even more elongate form. How near its affinities to this genus may be, cannot be ascertained, owing to want of important parts of the skeleton. but it differs in the important feature of the large, well developed ribs. ANIERI. PHILOS°. SOC.-VOL. XIV. 6