Cope.] ^S.") [JIavch 4, 1870. 



FOURTH CONTRIBUTION TO THE HISTORY OF THE FAUNA 

 OF THE MIOCENE AND EOCENE PERIODS OF THE UNITED 

 STATES. 



By E. D. Cope. 



ESCHRICHTIUS, Gray. 



ESCHRICHTIUS POLYPORUS, Cope. 



Species nova. 



Character. Ramus mandibuli with coronoicl process but little eleva- 

 ted ; form compressed witli narrowed acute superior margin, which is 

 not flattened posteriorly. On its inner face a wide shallow groove, in 

 which the inner series of foramina lie. Foramina of outer series large, 

 nviraerous. Size large. 



Description. This whale, from the form of the ramus mandibuli, is a 

 finner, and from the slightly developed coronoid process, allied to the 

 humpbacks. The coronoid, the anterior position of the dental foramen, 

 and the angular process, confirm these relationships. Whether it be a 

 Megaptera or Eschrichtius I am not prepared to state. Ear bullae of the 

 forms of both these genera occur in the strata in which the present 

 species was found, and future investigation must determine which are re- 

 ferable to the latter. Such a bulla of the form of and probably belonging 

 to, Megaptera, has been named Balaena mysticetoides, by Emmons. 

 (North Carolina Geol. Survey Tab.) 



The fragment which on the present species is based, is the proximal 

 two-fifths the left ramus mandibuli, with a considerable part of the con- 

 dyle. The direction of the shaft from a short distance anterior to the cor- 

 onoid process, is decurved. The inferior margin is slightly contracted be- 

 low the coronoid process and then for a short distance convex, and nar- 

 rowed into a ridge ; anteriorly it is most obtuse or convex transversely. 

 The inner face is plane at the coronoid process, the outer convex. An- 

 terior to this point the convexity is strong- ; at the distal end of the frag- 

 ment, mu-ch less marked. • 



The angular process has extended beyond the line of the condyle ; its 

 extremity is broken away. A wide groove separates it from the base of 

 the condyle on the iimer face of the ramus. The surface of the condyle is 

 transverse to the plane of the ramus, and is strikingly elevated above the 

 portion of the ramus anterior to it, being as high as the tip of the coro- 

 noid process. A low knob projects on the inner face of the ramus beneath 

 its anterior part, and below the groove. The dental foramen is large, and 

 is overhung by the thin incurved superior margin of the ramus. Its an- 

 terior margin terminates just behind the posterior part of the base of the 

 coronoid process. 



The pores of the inner series are small and numerous ; the last one is a 

 little anterior to the base of the coronoid process (34 lines). They are 

 situated in a wide shallow groove, which occupies a portion of the inner 

 face of the ramus below the upper edge. Their interspaces are not quite 

 equal ; thus twenty lines separate two, and four are included in thirty- 



A. p. S. — VOL. XI — 8e. 



