156 [August, 



The month is broad in ront, but not deeply cleft; its angle extending to the 

 vertical of the anterior rim of the eye. The latter is small, subelliptical in 

 shape, and situated near the upper surface of head; its horizontal diameter is 

 contained about six times in the length of the side of head. The body is an- 

 teriorly broader than deep; it diminishes gradually in both height and depth 

 towards the origin of the tail, which is quite compressed and very much reduced, 

 and terminated by a slender caudal fin. rounded upon its posterior margin. The 

 origin of the dorsal fin is situated a little in advance of the anus, but does not 

 unite with the caudal, between which and the posterior extremity of its base, a 

 space of three tenths of an inch is left; even the tips of its posterior rays do not 

 reach the base of the caudal. The anal begins a little further back than 

 the dorsal, is as deep as the latter is high, and extends likewise a little further 

 behind; the tips of its posterior rays nearly reaching the base of the caudal. 

 The pectorals are broad but slioit, the ventrals are imbedded in the membranous 

 disk peculiar to that group of fishes. 



D 14. A 13. C 3. 1. 5. 4. 1. 3. V 8. P 20 4- 3. 



The three inferior rays of pectorals are the stoutest, and situated under the 

 throat, connected with the disk, which is very large. The surface of the anterior 

 portion of the said disk exhibits large pavement-like cells. 



The ground color is greenish brown, with a mesh work of black lines all over 

 the head and body. The infe-ior surface of head and belly are dull yellow. 



From San Luis Obispo, Cal. 



LOPHOBRANCHU. 



49. Syngxatiitjsbrevirostris, G. Greatest length six inches and a half; head 

 forming about the eighth of it. Snout abbreviated, distance from anterior rim 

 of eye to tip of snout, equal to remaining portion of head. Dorsal fin quite low, 

 and thirteen twentieths of an inch long. Posterior margin of same fin nearly- 

 equidistant between tip of snout and extremity of caudal. Pectorals small. 

 No anal fin. Abdominal pouch, for the reception of the eggs after their laying, 

 very long. Caudal of medium size and rounded. 



D 30. C 1.4.4. 1. P 12. 



Ground color greenish, tessellated with brown. 



From San Diego, Cal. 



50. Svngnatiius leptorhynchus, G. Entire length six inches; head con- 

 tained in it six times and a half. Snout elongated and slender. Dorsal fin very 

 ow, and six tenths of an inch long ; its posterior margin nearer the extremity 

 of caudal fin than to the tip of the snout. Pectorals small. A rudimentary anal. 

 Caudal slender and rounded posteriorly. 



D 32. A 1. C 1. 4.4. 1. P 10. 



Dorsal region greenish yellow; sides bluish; abdomen whitish. Tail beneath 

 dull yellow. 

 San Diego, Cal. 



The Committees to which were referred papers by Dr. Leidy, read 

 Aug. 8th, by Prof. t Baird and Mr. Chas. Girard, read Aug. l l'l(\, and 

 by .Dr. Le Conte, read same date, severally reported in favor of publica- 

 tion in the Proceedings. 



Synopsis of extinct Jtfummalia, the remains of which have been discovered in the 



Koceiie Formations of Nebraska. 



By J-oskfh Leidy, M. D. 



CARNIVORA. 



1. Machairodus rRiM.Evus : Proc. Acad. Nat. Sc. 1851, v. 329; Owen's Re- 



port of a G^olog. Survey of Wisconsin, etc 1852, 504 ; Ancient Fauna of 

 Nebraska, 1853, 95. 



2. Dinictis ielina: Proc. Acad. lS51,vii. 



