134 PROCEEDINGS OP THE ACADEMY OF 



On AMPHIBAMUS GRANDICEPS, a new Batrachian from the Coal Measures. 



BY PROF. EDW. D. COPE. 



The recent additions to oar knowledge of the air-breathing vertebrates of 

 the carboniferous period, are of great interest to the comparative anatomist, 

 as furnishing new points in the series of structures between the Ganoidea and 

 Lacertilia, or new " generalized " types combining the structures of these and 

 of the Batrachia. 



I owe to Prof. Jos. Leidy, of our University, a specimen of a reptile, belong- 

 ing to the Illinois State Survey, in charge of Messrs. Meek and Worthen. It 

 was discovered by the latter near Morris, Grundy Co., 111., in a bed belonging 

 to the lower part of the coal measures. It is imbedded in a concretion of 

 brown limestone. The casts of the bones are. occupied by a white friable 

 mineral, which has probably percolated into them. 



This animal combines with its Batrachian, a few Lacertilian characters, 

 having some resemblance to Dawson's genus Hylonomus, and much affinity 

 with Prof. Wyman's Ranceps 1 y e 1 1 i i . Its squamous integument and narrow 

 nasal roof give it the somewhat Lacertilian physiognomy, more especially 

 Geccotian, in its broad cranium and orbits, its large marginal palpebral scales, 

 and rather short digits. Its true affinities are indicated by the presence of 

 two premaxillaries, with a squamoso-postorbital arch, as in Labyrinthodontia, 

 some Batrachia Gradientia, and Crocodilia ; its quadratojugal arch as in 

 Labyrinthodontia and Batrachia Salientia ; its posteriorly directed oblique 

 quadratum and lack of ribs, as in Batrachia Salientia ; its probably short 

 pelvis, short separate bones of the leg and fore-arm ; its opisthocaeliau dorsal 

 vertebra;, and long caudal neural spines, as in Batrachia Gradientia. It is 

 then the type of a group intermediate between the Labyrinthodontian and 

 Gradient Batrachians, distinguished from the former by the opisthocoelian 

 vertebrae, absence of ribs, and pleurodont dentition ; and from the latter by 

 the scaly integument, absence of ribs, and structure of the nasal and pre- 

 frontal regions. But one genus of Salamanders, Glossolega, has a similar os 

 quadrato-jugale, and but a part of one family, the Salamandridte, the post- 

 fronto-squamosal or posterior zygomatic arch. A ribless type might, however, 

 well exist among Gradientia, when we consider the great difference between 

 their developement in Pleurodeles on the one hand, and Amphiurna on the 

 other. From the Salientia the dentigerous mandible, squamosal arch, form 

 of vertebrae, sacrum and extremities, etc., widely distinguish it. To the Ba- 

 trachian orders Labyrinthodontia, Gradientia, Gymnophidia and Salientia, 

 the present may be added, under the name Xenorachia. 



The general form of the skull is much that of a frog, and large in proportion 

 to the size of the animal; its length is one-half that of the spinal axis from 

 the occiput to the middle of the sacral region, and five-sixths its own breadth 

 in the flattened specimen. The outline is not broadly rounded, as is usual 

 among Salamanders, but is slightly contracted, as in many frogs. The orbits 

 are large, regularly rounded, their longitudinal diameter one 'and one-half 

 times the frontal width ; their point of nearest approach is behind opposite 

 the position of the iris; one diameter measured obliquely, in advance of each 

 extends a little beyond the common premaxillary suture. 



The premaxillary bones have considerable horizontal extent, terminating 

 opposite the narial openings, each bearing eleven or twelve teeth. Their nasal 

 spines were in close contact, and do not appear to be prolonged backwards, 

 as in most Gradientia. The external nares are rather widely separated, as in 

 most Gradientia, the integument which they pierced roofing a large space be- 

 tween the median and peripheric bones of the muzzle. The roof of the nasal 

 cavities is a truncate cuneiform plate, whose apex joins that of the premax- 

 illaries. Its composition can only be conjectured, from the appearances pre- 

 sented by the specimen. It may be a superior ethmoid plate, as in the frogs 



[July, 



