1851.] 



239 



Several fragments were then exhibited of a much smaller animal than the last, 

 consisting of the greater part of the inferior and superior maxillae, the latter con- 

 taining the 4th premolar and the true molars perfect, having the same form as those 

 of Oreodon priscum. To this species, the name of Oreodon gracile was given. 



The posterior two inferior molars have the same form as the corresponding 



ones of Merycoidodon. 



Measurements of 0. gracile. 



Line of inferior molars to root of canine, . . . 25i lines. 



Greatest breadth of inferior maxilla, below the posterior 



molar tooth, 16i *' 



Line of superior molars, 26 " 



'< " true molars, 14 " 



Greatest breadth of the middle superior true molar, . 5i *' 



The fragment of a face before alluded to having the same form of the superior 

 true molars as Oreodon, but differing from it in having 3 cusps to the fourth pre- 

 molar, belonged to an animal very closely allied to the latter genus. It possesses 

 the remarkably large lachrymal depression, which in this fossil appears to have 

 been more hemispherical than in Oreodon. The depression being of such a strik- 

 ing character in Oreodon and in this genus, the name Cotylops was proposed for 

 the latter. The only entire tooth preserved in the fragment of Cotylops is the 

 third premolar, the crown of which is antero-posteriorly oblong, constricted in 

 the middle so as to give in outline the form of 8. It has a single cusp, and pre- 

 sents an oval fossa about two lines long, postero-internally ; and a heel or short 

 tubercle antero-internally. 



The species was named Cotylops speciosa. 



Measurements. 

 Length of line of 1st and 2d superior true molars, . . 10 lines. 



" " 2d, 3d, and 4th premolars, 



Antero-posterior diameter of 3rd premolar. 

 Greatest breadth of " " 



Diameter of lachrymal depression, . 

 Depth " u a . . 



The fragment of cranium for which was proposed the name Eucrotaphus,* 

 from its great resemblance to that of Oreodon, and its proportions, with the close 

 alliance of Oreodon to Merycoidodon, Dr. L. suspected belonged to the latter 

 genus. 



13 

 4i 

 2i 

 61 

 2i 



August 26th. 

 Vice-President Wetherill in the Chair. 



The Connmittee on the following, by Dr. Leidy, reported in favor of 

 its publication. 



Helminthological Contributio7is. No. 3. 

 By Joseph Leidv, M. D. 



Gen. Nov. SYNPLECTA.f 

 Body nematoid, cylindroid, distinctly and coarsely annulated. Head composed 

 of two trilobed portions, between which is the mouth. (Esophagus long, simple. 



Proc. Acad. Nat. Sci., Vol. v. p- 90. -j-jvv together; mtxut^ I twine. 



