NATURAL SCIEHCES OF PHILADELPHIA. 219 



Oestocephalus amphiuminus Cope. 



This species is represented by the imperfect crania and anterior portions of 

 the bodies of two individuals. They indicate an animal of the average size of 

 the Amphiuma means. 



The extremities of the vertebrae are deeply concave, but the centra are so 

 long as to prevent the concavities entering more than one-fifth of the latter, 

 each. The diapophyses are behind the middle, and are broad, curved back- 

 wards, and acuminate, as in Amphiuma. The centra have a prominent median 

 line below, with a longitudinal concavity on each side. Five of them a little 

 exceed an inch in length. Neural spines are nowhere visible. The humerus 

 is longer than the scapula and is considerably dilated distally ; the scapula 

 sliglitly dilated at its superior extremity. 



The dermal armature commences immediately behind the head, and forms a 

 band of 14 lines in width ; measuring across the spine-like scales, in a width 

 of a line, four cylinders may be counted. The external portions are carried 

 backwards, the interior nearly straight, those of the anterior more delicate 

 than the posterior. 



The head is wedge-shaped with regularly acuminate sides. The top of the 

 cranium is somewhat broken in the specimen ; the portions preserved are 

 amooth, and the longitudinal suture is distinct for a considerable distance. The 

 angle of the mandible is produced considerably behind the occiput and is 

 enlarged and rounded. The end of the muzzle is broken away, and the region 

 of the orbits so fractured as to render their precise location uncertain. The 

 superficial layer of the cranial bones is nowhere clearly visible, so that it can- 

 not be ascertained whether it is sculptured or not. The quadrate bone pro- 

 jects well posteriorly. Some fragments indicate small cylindric teeth, as in 

 Amphibamus, but they are not characteristic. 



Measurements. 



Lines. 



Length cranium without muzzle IT-S 



Width " posteriorly 11-5 



Length scapula ., 2-1 



" humerus 2-5 



" of sixth vertebra from skull 3 



Extent diapophyses 3-5 



Width centrum 15 



This species was discovered by Prof. Jno. S, Newberrj"-, at Linton, Eastern 

 Ohio, in the slate of the coal measures. , Mus. Columbia College. 



The characters of the genus are further shown by a part of another indi- 

 vidual in the same coal slate matrix. The cranium and anterior portion of the 

 vertebral column only are preserved, the latter so much injured as to render 

 the vertebral characters very obscure. As in the other, the bristle-like scales 

 extend along the dorsal region to near the cranium. The anterior two-fifths of the 

 ventral side shows a large number of small oval scale- like bodies, which 

 belonged undoubted]}- to the animal and were probably dermal scales. They 

 are, however, neither regular in form or position. Close behind the head two 

 or three long bones of the fore limbs have been exposed. They are slender, 

 and similar to those of the last specimen. 



The cranium, though without the muzzle, shows its long wedge- shape. The 

 maxillary bone cannot be distinguished, nor can the orbits be made out ; one 

 ramus mandibuli is pretty well preserved ; it shows no coronoid process. 

 Twenty-one teeth may be counted on a portion a little more than one-third its 

 length. The anterior eleven of these are abruptly longer and stouter than the 

 others. They are, except a few most anterior, in pairs, i. e. with a slight va- 

 cancy between every two. The larger ones were broken at the bases, exhibit 

 a moderate pulp cavity ; the smaller, a large one extending to near the tip. 

 Several, though not all of the larger teeth, display a shallow groove on the ex- 



1868.] 



