﻿DIPTERIDJR. 245 



plausible by A. Giinther, Phil. Trans. 1871, p. 557, and A. Fritsch, 

 Fauna dor Gaskohle, vol. ii. (1888), p. 91 ; its reference to the 

 mandible, however, seems more probably correct, as remarked by 

 R. H. Traquair, Ann. Mag. Nat. Hist. [5] vol. ii. (1878), p. 15. 

 Very similar also is an imperfect mandible, from an unknown 

 formation and locality, named Archceotylus igaotus, H. von Meyer, 

 Palaeoutogr. vol. xi. (1864), p. 285, pi. xliv. 



Genus CONCHODUS, M'Coy. 



[Ann. Mag. Nat. Hist, [2] vol. ii. 1848, p. 312.] 



Syn. Cheirodus, C. H. Pander (non M'Coy), Ctenodipt. devon. Syst. 

 1858, p. 33. 



A provisional genus comprising species of small size, known only 

 by the detached dental plates. Dental plates broad, thin, irregularly 

 triangular, almost or quite smooth, with few short radiating ridges 

 at tho outer border. 



Two species of this genus are recognized, but neither is repre- 

 sented in the Collection : — 



Conclioclus jerofejewi, C. H. Pander, Ctenodipt. devon. Syst. (1858), 

 p. 61, pi. vi. figs. 15-22 (Cheirodus) : Ceratodus lateralis, 

 E. von Eichwald, Bull. Soc. Imp. Nat. Moscou, vol. xix. 

 (1846), pt. ii. p. 299 (name ouly) : Cheirodus lateralis, 

 E. von Eichwald, Leth. Rossica, vol. i. (1860), p. 1542.— 

 Devonian; N.W. Russia. [School of Mines, St. Petersburg.] 

 Conchodus ostreceformis, F. M'Coy, Ann. Mag. Nat. Hist. [2] 

 vol. ii. (1848), p. 312, and Brit. PaLeoz. Foss. (1855), 

 p. 593, pi. ii. c. fig. 7. — Upper Old Red Sandstone ; Scat 

 Craig, Elgin. [The type species, founded upon a dental 

 plate in the Woodwardian Museum, Cambridge.] 



Genus GANORHYNCHUS, Traquair. 

 [Geol. Mag. vol. x. 1873, p. 555.] 



A provisional genus at present incapable of definition, comprising 

 large Palaeozoic Dipnoan fishes in which the extremity of the snout 

 (as also presumably all the external head-bones) is enveloped in a 

 thick layer of punctate ganoine. 



Ganorhynchus woodward!, Traquair. 



1873. Ganorhynchus ivoodwardi, Pt. II. Traquair, Geol. Mag vol. x, 

 p. ooo, pi. xiv. 



Type. Extremity of snout ; British Museum. 



