Cope.l ^^■^ [Mayfi, 



greatest width of the latter is more than two-thirds its depth. Tlie pelvic 



supports of the ventral fins are slender, and about half the length of the 



fin. The pectoral fins are not elongate. 



The scales extend over the top of the head to or beyond the orbits. 



They also extend out on the ramus of the under jaw. Those of the fins 



are quite small ; they extend to a considerable distance on the unpaired 



and on the caudal fins. 



M. 



Total length of the largest specimen 0.19 



Do. No. 2, smaller example (with caudal) 0.12 



Length of head of do 0.044 



Depth of do. posteriorly about 0.036 



Length base spinous dorsal 0.0265 



" posterior " ray 0.017 



" operculum 0.0125 



'' maxillary bone about 0.0145 



Depth No. 3, at base 1st dorsal 0.045 



" " " anal, 1st ray 0.0325 



Length basis anal=basis caudal 0.0162 



" caudal fin 0.034 



Tertiary strata of Green River, Wyoming; Dr. F. V. Hayden, Coll. Mus. 

 Smithsonian. 



Clupea humilis, Leidy. 

 Proc. Acad. Nat'l Sciences, 1856, 256. 



Vertebrae 34. Depth 2h to 2| lines in length exclus caudal fin (2^ times, 

 Leidy). Scales large; 1. transverse 11-12. 

 A very abundant species in the shales. 



Clupea pusilla, Cope. 

 Greatest depth contained four times in the total length, or 3. 5 times to 

 basis of caudal fin. Length of head 3.2 to basis caudal;— this measure- 

 ment may require revision, as the end of the muzzle is slightly injured. 

 Orbit large, contained twice in length of head behind it. Middle of dorsal 

 near the middle of length, and about over the origins of the ventrals. D. 

 II. 11, V. 7. Pectorals extending half way to ventrals. Vertebrae 29-30, 

 dorsals 19-30. Ventral keeled ribs 18. Anal fin lost. Caudal peduncle slen- 

 der, caudal fin deeply furcate. Length M. 044; greatest depth M. Oil. 



The present species is about half the size of the last, and of consider- 

 ably less proportionate depth. 



Cyprinodon levatus. Cope. 

 Anterior margin anal fin commencing a little behind opposite the pos- 

 terior margin of the dorsal. Vertebrae 10. 14. I. Radii D. 8, A. II. 8, V. 

 8. Caudal fin deeply furcate; first anal ray strong. 



General form elongate, the greatest depth contained three times in the 

 length between the scapular arch and the basis of the caudal fin. Scales 

 preserved, small ; seven longitudinal series above,' and seven below the 

 vertebral column, probably two rows concealed by it. The caudal peduncle 

 is rather contracted for the genus. Length from scapular arch to extrem- 

 ity of caudal M. 0335; depth at origin dorsal fin M. 008. 



