BUFFALO SOCIETY OF NATURAL SCIENCES 171 



occupies over one- third the length of the plate (at the middle ridge). 

 Outermost denticles of each ridge rounded, succeeding ones somewhat 

 compressed, and in the principal ridge tending to fuse into a com- 

 pressed edge. Number of denticles in principal ridge, two or three; 

 in second ridge, three; in third, four; in fourth, five. In the third 

 and succeeding ridges the outermost denticles are more or less dis- 

 crete, i. e., not confluent at their bases. All denticles, as well as inter- 

 spaces between them, covered with minute punctae. 



Remarks. — This species is closest to Dipterus flabelliformis New- 

 berry, and D. pectinatus Eastman. It is distinguished by the much 

 larger smooth, central area; by having fewer ridges, and in each 

 ridge fewer and more discrete denticles. In the third longest ridge 

 of D. flahelliformis there are nine or ten denticles, whereas in the 

 third ridge of the present species there are only four. 



Dipterus valenciennesi Sedg. & Murchison 



E 2518 A fine head-shield, 5 cm. in length, showing prettily all the 

 head plates and the sensory canals. 



Old Red Sandstone; Weydate, Thurso, Scotland, 



Dipterus nelsoni (Newberry) 



E 2519 Right mandibular dental plate. Chemimg conglomerate? 

 N. W. Pa. Collected by J. F. Carll. 



Dipterus sp. 



E 2015 A small dental plate, in matrix (PI. 56, fig. i). Conodont 

 bed; Eighteen Mile Creek, near North Evans, Erie 

 . County, N. Y. Collected by W. L. Bryant. 



Scaumenacia curta (Whiteaves) 



(PI- 57, figs. 3, 4; text-fig. 57) 



This is now one of the best known of Devonian lungfishes, the 

 exquisitely preserved specimens found in the Scaumenac Bay region 

 of Canada having afforded a knowledge of every detail of its external 

 structure. A restoration of this form has been published by Hus- 

 sakof^° (text-fig. 57). 



30 Hussakof, L.: Notes on Devonic fishes from Scaumenac Bay. ^V. Y. Slate Museum, Bull. 15Q, 

 p. 135, 1912. 



