PEKCOMOEPHI. 85 



ridges continued round the central point proximally, distally forming para- 

 bolic curves, the less median not completed, but interrupted by the margin 

 of the scale. Near the margin all the ridges become gently zigzagged. 



There is no depression between the two portions of the dorsal fin, 

 though the cartilaginous portion is the more elevated. Laid backwards, the 

 latter is in line with the extremity of the anal, and both extend beyond the 

 basis of the caudal. 



The affinities of this genus are rather obscure, but are in some degree 

 to that aberrant family of Physoclysti, the Aphredodirida. This is indi- 

 cated by the increased number of ventral radii, the slender separated pubes, 

 and the reduced number of interneural spines. The Aphredodiridce betray 

 Physostomous tendency in the same characters, with still greater reduction 

 of the spinous dorsal and anal fins, though its ctenoid scales and spinous orbital 

 and preopercular bones are of Physoclyst significance. In Asineops the 

 scales are cycloid, and the cranial bones unarmed. The ventral fins occupy 

 nearly the same position as in the extinct genus Erisniatopterus Cope, which 

 accompanies it. There is at least in these genera another illustration of 

 the approximation of forms now very distinct, in past periods. The pubes 

 are, however, supported by the clavicles in Asineops, and by the ^wst-clavicles 

 in Erismatopterus, though the latter bones are very long in Asineops also. 

 Asineops will thus constitute a family Asineopidce difieriug from the Aphre- 

 dodiridas in the simple pubes. I suspect that the genus Pygceus of Agassiz will 

 be found also to belong to it, though the increased number of ventral 

 radii is not assigned to it in the Poissons Fossiles. Some of its species may 

 even be found to belong to Asineops. Nine species are described by Pro- 

 fessor Agassiz, all from Monte Bolca, in Italy, from an Eocene stratum. 



Asineops squamifrons Cope. 



Proceed. Amer. Philos. Soc, 1870, p. :381. Annual Eeport U. S. Geol. Surv. Terrs.,, 1870, p. 426. 

 Asineops viridensis Cope. Annual Eeport 1870, p. 426. 



Plate rX, fig. .5; PI. x. 



General form suboblong, the greatest depth just behind the head, 

 and contained two and a half times in the length exclusive of caudal fin. 

 Radii D. VIII— IX, 14; A. II, 11-12; C.14;V.I, 7; P.?ll?13. Scales5— 



