252 ROYAL SOCIETY OF CANADA 
“ Coccosteus is already well known to occur in the typical Upper 
Old Red Sandstone; and it is interesting to note that in Russia, as in 
Canada, the genus is found in association with species of Bothriolepis.” 
SUB-CLASS IV. DIPNOI 
GENUS SCAUMENACIA, Traquair. 
Scaumenacia, Traquair. 1893. Geol. Mag., dec. 3, vol. x, p. 262. 
re Dollo. 1895. Sur la Phylogenie des Dipneustes, extrait du Bull. 
de la Soc. Belge, de Geol., de Palæont., et d’Hydrol., tome ix, pl. v, 
fig. 6; which is a reproduction of an original restoration of the 
only known species of this genus, by Dr. Traquair. 
This genus is said to be “characterized by its double dorsal fin,” 
or two dorsal fins, which are thus described by Traquair: ; 
“The anterior dorsal commences far forwards; it is low and frin- 
ging in character, and the length of its base is contained two-and-a-half 
times in that of the posterior dorsal, the interval between the two fins 
being equal to one-third of the length of the base of the anterior. The 
base of the second dorsal extends to a point a little beyond the com- 
mencement of the lower lobe of the caudal, but as its rays are long, 
and the posterior ones directed nearly horizontally backwards, the fin 
seems to extend near to the tip of the tail. It does not, however, form 
a continuous dorso-caudal as in Phaneropleuron, as hitherto described, 
or in Ceratodus or Uronemus, and Mr. Whiteaves is certainly in error 
in making it do so in his restored figure.” “As regards the caudal fin 
it is in reality heterocercal, the upper lobe being represented only by 
very short rays towards the tip of the body prolongation, while on the 
ventral aspect the lower lobe is of the triangular form characteristic 
of Dipterus. Indeed, the resemblance of the fins to those of D. mac- 
cropterus, Traq., from John O’Groats’, is very remarkable, the most 
striking difference being the more extended base and fringing form of 
the anterior dorsal in the species under consideration. Dipterus Valen- 
ciennesti, D. macropterus and Scaumenacia curta form then a complete 
and most interesting series as regards the configuration of their dorsal 
fins; in the first both dorsals are short based, in the second the posterior 
dorsal has a base of considerable length, in the third the anterior dorsal 
is long based, while the base of the posterior one is still longer than in 
the second.” Op. cit. supra, p. 263. 
In the specimens upon which the restoration of this species in the 
Transactions of this Society for 1888 was based. neither Mr. Lambe 
nor the present writer were able to find any separation between the 
caudal fin and the second dorsal. To the writer they seemed to indicate 
a proportionately shorter and deeper fish than that since represented in 
Traquair’s restoration of the genus from other specimens. 
