PEECOMOEPHL 99 



species of the genus, agreeing in this respect with another which I have 

 seen in the museum at Salt Lake City. It is also more elongate in its form, 

 and is further characterized by its large scales. The more general charac- 

 ters are, the undivided dorsal tin ; the wide interneural spines, and the well 

 developed basilar interneurals. Also the haemal spines of the caudal fin 

 retain the division into three or four parts. The vertebrae have a flat medi- 

 an, lateral rib, bounded by a fossa above and below. The lower border of 

 the inferior fossa on the dorsal vertebrae is deflected. The anterior base of 

 the neural spine is excavated on the second, third, and fourth vertebrae, 

 behind the scapular arch. The lateral rib of the second is oblique vertical. 

 On the fifth and sixth it has an excavated, down-looking superior border. 

 The scales, which are beautifully preserved, though much disarranged, are 

 about as deep as long, with the anterior border subtruncate. The borders, 

 excepting the posterior, are marked with four lines of growth, and from fivo 

 to ten grooves radiate from the center, across the posterior border lines. 

 There are numerous minute elevated points on the center of the scale, and 

 the same reappearing on the posterior border, give the ctenoid character. 



Radii: D. XI — 12; A. -f 21 -{-. The number of the rays of the infe- 

 rior fins cannot be ascertained, but there may be counted between the first 

 and last, the impression of eleven interhaemal spines. The dorsal spines 

 are very stout, and the first is very short. The ventral spine is not very 

 long, but is very robust. The interhaemals that support the anal spines 

 are extraordinarily robust. The outline of the body is an elongate oval, 

 the depth at the ventral fin entering the length without the caudal fin (or 

 head) two and two-fifths times. Vertebrae: D. from scapular arch, 8; C. 16. 



Measurements. 



M. 



Length ■svithout head and caudal fin 255 



Depth at posterior base and fin 044 



Length of series of caudal vertebrie 140 



Depth from vertebra to ninth dorsal spine : 026 



Vertical diameter last dorsal vertebra OH 



Length of fifth dorsal spine 052 



From the calcareous shales of the Lower Eocene, near Manti, Utah. 



A small specimen, apparently of the young of this species, was sent me 

 by Dr. A. S. Packard. It is of a more elongate form than any of the other 



