[wHirzaves] FOSSIL FISHES OF THE DEVONIAN ROCKS 247 
Genus MESACANTHUS, Traquair. 
Mesacanthus, Traquair. 1888. Geol. Mag., dee. iii, vol. v, p. 511. 
“The small Acanthodes-like fishes of the Scottish Lower Old Red 
Sandstone differ from Acanthodes of the Carboniferous and Permian 
rocks by the presence of a pair of small intermediate spines on the 
belly between the pectoral and ventral spines. Here may be included 
Mesacanthus pusillus, Ag. sp., M. Peachu, Egert. sp. (incl. A. coriaceus 
Egert.), and M. Mitchell, Egert. sp.” Traquair. 
(2) MESACANTHUS AFFINIS (Whiteaves). 
Acanthodes Mitchelli (?) Egerton. Whiteaves. 1887. Trans. Royal Soc. Canada 
for 1886, vol. iv, sect. iv, p. 107. 
Acanthodes afinis, Whiteaves. 1889. Do. for 1888, vol. vi, sect. iv, p. 91, pl. v, 
j figs. 1 and la—f. 
Mesacanthus affinis, Traquair. 1890. Geol. Mag., dec. 8, vol. vii, p. 16. 
Acanthodes affinis, A. Smith Woodward. 1891. Cat. Foss. Fish. Brit. Mus. 
jolt any JOH, de 
Type.—Nearly complete fish; in the Museum of the Geological 
Survey of Canada. 21 
“Owing to the very distinct presence of a pair of small spines 
intermediate between the pectorals and ventrals in Acanthodes Mitchelli, 
and in A. Peachii, Egerton, I have proposed to include them in the new 
genus Mesacanthus, including also, from its general aspect, A. pusillus, 
Agassiz, from the Moray Firth beds, although our specimens of the 
latter are not well enough preserved to show them. Here I would also 
place M. affinis, as in one specimen I at least imagine I see one of 
those minute intermediate spines.” ‘Traquair. 
(3) DIPLACANTHUS HORRIDUS, Woodward. 
Diplacanthus horridus, A. Smith Woodward. 1892. Geol. Mag., dec. 3, vol. ix, 
je A Ab xp ale 
Types.—Two imperfect specimens of the fish; in the British 
Museum. 
SUB-CLASS II. OSTRACODERMI. 
GENUS EUPHANEROPS, Woodward. 
Euphanerops, A. Smith Woodward. 1900. Ann. & Mag. Nat. Hist., ser. vii, vol. v, 
p. 418. 
“ No fragments of armour resembling that displayed by this fossil 
appear to have been hitherto described. The animal must thus be 
; See. IV., 1907. « 15. 
