386 PALEONTOLOGY OF OHIO. 



place, terminating in a short obtuse ungueal phalanx. Proximally to 

 the first of the series is another, rather shorter than the latter, perhaps 

 the first of the digit. Several other phalanges are irregularly distrib- 

 uted, and there are several metatarsals not well preserved. There were 

 four or five digits. 



Length of entire caudal series, 0.195 m. ; width (total) at ninth, .021; 

 width (total) at thirty-sixth, .02; length of four phalanges in place, .014. 



The hind foot was evidently rather elongate, though its proximity to the 

 vertebral column suggests that the proximal part of the limb was not so. 



In size this species is about equal to the Urocordylus Wandesfordii, 

 Huxl. The caudal spines differ in the greater attenuation of the neural 

 series, and the presence of a basal lamina on the haemal, judging from 

 Huxley's account of the latter. 



Oestocephalus eectidens, Cope. 



Transactions American Philosophical Society, April, 1874. 



Indicated by a left dentary bone, with its teeth and external surface 

 ■preserved. The latter is nearly smooth and without sculpture. The 

 . outer face is convex, and the general form is slender, but not curved up- 

 ward at the extremity. Teeth straight and conic, apex acute; no visible 

 -grooves of the surface ; eleven in .005 m., closely placed, and of equal 

 lengths. The extremity of the dentary does not exhibit teeth, but they 

 may be concealed. 



Length of dentary, 022 m. ; length of tooth line, .0152 ; depth of den- 

 :tary at last tooth, .0027. 



This represents a smaller animal than does the skull of 0. remex, 

 „and differs much from the latter in the more closely placed and perfectly 

 .straight teeth. 



I describe here a specimen which is closely related as to size with the 

 0. rectidens, and is probably a member of this genus; but the specific 

 reference will remain uncertain till other portions of the skeleton are 

 discovered. Those preserved consist of twenty-five caudal vertebrae, 

 probably from the anterior part of the column. There are, therefore, no 

 ribs nor ventral armature. The centra are rather elongate and expand- 

 ed at the extremities ; the neural arches have a close union. There are 

 no diapophyses, but the fan-shaped and striate neural 'and haemal spines 

 are present. They are, however, shorter than in 0. remex, and not so ex- 

 ;posed as in the species of Ptyonius. The bases are quite narrow. Their 

 reduced size may be derived from the following measurements : Length 

 of three centra, .0086 m. ; extent of neural and haemal spines, .0087. 



