358 
CROSSOPTERYGII. 
P. 4587. Type scale, well preserved, much resembling the original 
of Roemers fig. 2 , hut less symmetrical; shown, of three- 
halves the natural size, in PI. XYI. fig. 3; Yolpersdorf, 
Glatz. Enniskillen Coll. 
P. 4586. Right operculum, 0'019 in depth, and equally broad, the 
hinder border sharply angulated about its middle point, 
and the lower border twice as long as the upper ; Yolpers¬ 
dorf. Enniskillen Coll. 
The following specimens also pertain to this genus :— 
P, 789. Two small scales, inner aspect; Coal-Measures, Pictou, 
Nova Scotia. Egerton Coll. 
Genus GYROPTYCHIUS, M‘Coy. ~ ! 1 " ~ 
[Ann. Mag. Nat. Hist. [ 2 ] vol. ii. 1848, p. 307.] 
Syn. Glyptolepis, L. Agassiz, Poiss. Foss. Y. G. R. 1844, p. 62 (in part). 
Rody much depressed anteriorly, with ovoid scales, of which the 
exposed portion is probably covered with a thin film of ganoine, 
while the inner face is marked by a prominent median ridge and 
punctations posteriorly. Head-bones tuberculated. No ossified 
vertebrae. First dorsal fin opposed to the pelvic pair, and the second 
dorsal to the anal; tail almost diphycercal, the upper lobe of the 
rhomboidal caudal fin being relatively large. 
This genus comprises fishes of small size, and is very closely related 
to Rliizodopsis : the scales appear to differ from those of the latter 
merely in the substitution of a prominent long ridge for the median 
inner boss. 
Gyroptychius microlepidotus (Agassiz). 
1844. Glyptolepis microlepidotus , L. Agassiz, Poiss. Foss. V. G. R. p. 65, 
pi. xxi. a . figs. 3-7. 
1848. Gyroptychius angustus ) F. M‘Coy, Ann. Mag. Nat. Hist. [2] vol. ii. 
p. 308, woodc. figs. a-c. [AYoodwardian Museum, Cambridge.] 
1855. Gyroptychius angustus, F. M’Coy, Brit. Palasoz. Foss. p. 596, 
pi. ii. c. fig. 2. 
1860. Gyroptychius angustus ?, C. H. Pander, Saurodipt., Dendrodont. 
&c. devon. Syst. p. 79, pi. vi. figs. 1-7, pi. vii. figs. 1-3. 
1861. Gyroptychius, T. H. Huxley, Figs, and Descrips. Brit. Organic 
Remains (Mem. Geol. Surv.), dec. x. p. 3, woodc. fig. 3. 
1875. Gyroptychius angustus, R. H. Traquair, Trans. Roy. Soc. Edinb. 
vol. xxvii. p. 395. 
1888. Gyroptychius microlepidotus , R. H. Traquair, Geol. Mag. [3] 
vol. v. p. 514. 
