170 CATALOG OP FOSSIL FISHES IN THE MUSEUM 



reflexed upward so as to produce a deep excavation between hump 

 and apex. In fact, in some of the later spines, for instance, the small 

 species S. erectus Eastman, and -S. exilis Hussakof, both from the 

 Waverly, this is carried to an extreme, the apical axis being at right 

 angles to the hump. 



Stethacanthus depressus (St. John & Worthen) 

 (PL 54, fig. 3) 



E 2516 Impression of a small spine in sandstone; also a squeeze of 

 same in dental wax. 



The specimen, though small, is complete and shows well 

 the characters of the species.''^ Length 30 mm. (apex 

 missing); height at posterior border of hump, 8 mm. 



Top layer of ' 'Second Mountain Sandstone" (Catskill) ; 

 Crawford County, Pa. , Carll collection. 



Ichthyodorulite, indet. 



E 1907 A thin, fragmentary spine, or plate, with serrated edges, 

 and a rounded central axis which gives it somewhat the 

 appearance of a fragment of a Machcer acanthus spine. 

 Perhaps an Arthrodire plate. 



DIPNEUSTI 



Dipterus gemmatus, n. sp. 



(PI. 56, figs. 2, 2a) 



E 2517 Type. — A small dental plate on a piece of limestone. 



Formation and Locality. — Conodont bed (Genesee) ; Eighteen Mile 

 Creek, near North Evans, Erie County, N. Y. Collected by W. L. 

 Bryant. 



Dental plate small, about 13 mm. in length (antero-posterior di- 

 ameter), its greatest width about two-thirds its length. Ridges, five 

 or six, tuberculated, radiating from a smooth central area which 



'' The specimen figured by Eastman in Bull. Mus. Compar. Zool., xxxix, 216, fig. 15, as Stethacati' 

 thus depressus, is incorrectly referred to this species. 



