39 



PISCES. 



1 SYi^ENTOGKATHI. 



PELEOOEAPIS, Cope, gen. nov. 



This genus embraces fishes with strongly ctenoid scales and abdominal 

 ventral fins ; there is a spinous dorsal tin apparently short, and not con- 

 tinued over the ventrals. The ribs and apophyses are slender, and 

 the dorsal vertebrae short and pitted. The pubic bones consist of two 

 antero-posterior plates, in contact on the middle line. The anterior por- 

 tion projects to a median angle, and there is an angular projection of the 

 lateral border. From the angle formed by these borders, a long cylind- 

 ric rod projects forward; those of opposite sides slightly converging. 



The general relations of this form are to the families which combine 

 the features of the orders of physoclystous and physostomous fishes, 

 namely, Sconihresocidw, Athennidce, &c. The pelvis has considerable 

 resemlilance to that of those families, but especially to that of Exocoetus. 

 Prom this it presents subordinate differences. 



Pelecorapis vaeius, sp. nov. 



Eepresented by portions of perhaps two individuals, the larger of 

 which inclndes a considerable part of the body, the head and tail being 

 absent. On this specimen it is evident that the scales diminish in size 

 toward the posterior part of the body, where they are small ; on the ante- 

 rior region there are two scales exposed in an oblique series, in 6 mil- 

 limeters ; on the posterior region, 3| and 4 in the same. The concealed 

 portions of the scale are sculptured with minute contiguous concentric 

 grooves, without any radii. The exposed portion is thickened with a 

 cementum-like layer, which is marked with a few radiating lines of pores 

 which sometimes unite into an irregular groove. Teeth of the comb 

 numerous and strong. Depth of body at pelvis, 0°'.074 ; length of pelvis, 

 0'".040; of lamina, 0'^.022; of rod, 0'^.023; greatest width of pelvis, 

 0'^.023; width at basis of rods, 0'^.014; length of 17 consecutive verte- 

 brae, 1™.05 ; diameter of a dorsal vertebra, 0'".007. 



Discovered by Professor Mudge in a lead-colored clay, probably of 

 the Benton epoch, 20 feet below the Inoceramus bed, 2 miles west of 

 Sibley, Kansas. 



ISOSPOXDYLI. 



POETHEUS, Cope. 



Proceed. Amer. Philos. Soc, 1871, 173; loc. cit, 1872, 331. 



Additional material establishes as correct the reference of sharp-edged 

 compound rays to the pectoral fins, and narrower, simple ones to the 

 ventrals; while the presence of a frontoparietal fontanelle is doubtful. 

 The number of teeth in the premaxillary bone is subject to some varia- 

 tion, there being occasionally, besides the principal ones, a small acces- 

 sory on one or both sides. 



PoETHEUS MOLOSSUS, Copc, Proceed. Amer. Philos. Soc, 1871, 173; 

 1872, 333. 



Common in the Mobrara Cretacious of the Smoky Hill region, Kansas. 



