G38 



GEOLOGICAL SURVEY OF THE TERRITORIES. 



Phareodon sericeus, Cope, spec. nov. 



Established on tliree teetli wliicli (lifter from tliose of the P. acutus in 

 their large size and stont conic form ; also in having the basal striation 

 liner, parallel, and extending over half the length of the crown. The 

 basal portions as preserved are black, the apex white, and with a 

 sliglitly abrupt contraction. 



Measurements. 



From Upper Green Eiver. 



EHINEASTES, Cope. 



Proceed. Amer. Pliilos. Soc, 1872, p. 486. (Published Angnst 20, 1872.) 



A genus of Nematognathi which differs from Phareodon in possessing 

 the usual band of bristle-like teeth on the dentary bone, the series 

 being numerous, (in E. calvus.) The basi-occipital bone exhibits a pit 

 on the middle line below, and a surface for attachment for the inferior 

 branch of the posttemporal on each side, {K. calvus, E. smithii.) The 

 modified anterior vertebral mass is deeply grooved below, {E. smithii.) 

 The cranium is covered with a rugose exostosis, {E. jKltatus, E. calvus, 

 E. smithii,) and has a strong closed groove in the ))osition of the usual 

 Ironto-parietal fontanelle. The vertebrae {E. smithii) are short, and the 

 sides of the centra only striate with the circumference. There are no 

 lateral pits, but a pair above and a pair below, with a oo-ossified apophy- 

 sis at the base of one of them. 



The spines preserved belong chiefly to the pectoral fin. They are 

 strongly striate and weakly dentate, and have the usual hinge with 

 superior recurved flange above, and two embracing i)rocesses below, 

 at the base. The dorsal spine is weaker in E. calvus, but strong in E. 

 peltatus. 



This genus is allied to the recent Ichthcclurus, but difl'ers (E. smithii) 

 in the vertebrie, and in the rough exostoses of the cranial bones. In 

 E. peUatus the supra-occipital siiield has a great mass and extent, but 

 in E. calvus it is not much more extended than in Ichthwlunis. 



The expedition obtained remains of four or five species of this genus, 

 the first of the order found extinct in this country. 



I. Ehineastes-; a large, massive nuchal shield. 



Cei)halic ossification pappilliform E. pcltatus. 



Ossification in rugose lines E. raduhis. 



II. Astephus ; nuchal shield narrow and short. 



Cephalic ossification in smooth lines ; one basi-occipital 



pit ; pectoral spines serrate on both edges E. smithii. 



Tliree basi-occipital pits; pectoral spines serrate on 



both edges E. calvtis. 



Pectoral spines serrate behind only ; curved E crcuatus. 



The cephalic bones of the last named are unknown, as \v<.il as the 

 ispines of E. raduhis. 



