DIPTERIDiE. 
245 
plausible by A. Gunther, Phil. Trans. 1871, p. 557, and A. Pritseh, 
Fauna der Gaskohle, vol. ii. (1888), p. 91; its reference to the 
mandible, however, seems more probably correct, as remarked by 
E. H. Traquair, Ann. Mag. Nat. Hist. [5] vol. ii. (1878), p. 15. 
\ery similar also is an imperfect mandible, from an unknown 
formation and locality, named Archoeotylus iguotus, H. von Meyer, 
Palaeontogr. vol. xi. (1861), 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. * ^ i f ^ tff.S't. 
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 the outer border. 
Two species of this genus are recognized, but neither is repre¬ 
sented in the Collection :— 
Conchodus 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 only) : Cheirodus lateralis , 
E. von Eichwald, Leth. Eossica, vol. i. (1860), p. 1542.— 
Devonian; NAY. Eussia. [School of Mines, St. Petersburg. ] 
Conchodus ostreceformis, E. M‘Coy, Ann. Mag. Nat. Hist. [2] 
vol. ii. (1848), p. 312, and Brit. Palasoz. Foss. (1855), 
p. 593, pi. ii. c. fig. 7.—Upper Old Eed Sandstone; Scat 
Craig, Elgin. [The type species, founded upon a dental 
plate in the Woodwardian Museum, Cambridge.] 
Genus GANORHYNCHUSj Traquair. 
[Geol. Mag. vol. x. 1873, p. 555.] 
Wi ** i 
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. 
Ganorhynehus woedwardi, Traquair. 
1873. Ganorhynehus ivoodwardi, E, H. Traquair, Geol, Mag vol. x, 
p. 555, pi, xiv. 
Type. Extremity of snout; British Museum. 
