360 On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 
any sulcus or groove. The portion of base implanted in the body of the fish was 
small, being ‘65 of an inch, equal to about one-eighth the entire length of the spine. 
This unique specimen was collected by the late Sir Roderick Murchison, and 
placed in the Geological Society's museum. Its closest relationship appears to be 
with Acondylacanthus, N. and W., and Lispacanthus, Davis. It differs from the 
former in having no surface ornamentation or posterior denticles, though its general 
contour is similar; and from the latter in the more evenly circular form of the base 
and spine generally, and also in the absence of the deflexure characteristic of 
Inspacanthus retrogradus. 
I propose for the present to place the specimen in the genus Lispacanthus ; though 
not agreeing in all particulars with the characters of that genus, it appears prefer- 
able to include it rather than institute a new genus for its especial occupation. 
Formation and locality : Mountain Limestone, Kendal Fells, Westmoreland. 
Ez coll. Geological Society, London. 
Genus.—Dipriacanthus, M‘Coy. 
Dipriacanthus—M ‘Coy, “ Brit. Palioz. Foss.,” p. 627. 
‘Spine, small, arched, tapering, much compressed, minutely and irregularly 
tuberculated ; two rows of small conical teeth on the posterior margin, and two 
rows of larger adpressed teeth on the anterior face directed upwards.’—(M‘Coy). 
Prof. M‘Coy in the “ Annals and Magazine of Nat. Hist.,” described two species 
of Dipriacanthus, viz:—D. Stokesti and D. falcatus. The only specimen which I have 
seen of the latter is in the museum of the Geological Society, London. The name 
attached is in the handwriting of Prof. M‘Coy, so that this specimen is probably 
the one described. It is about one inch in length and possessed of denticles on the 
posterior margins, but I fail to find any trace of denticulation on the anterior one. 
As this specimen does not possess the characters distinguishing the genus as de- 
fined by M‘Coy, it will not be included in the genus. Dipriacanthus stokesw is an 
altogether different specimen with a peculiarly expanded base which does not con- 
form to any ordinary forms. It resembles to some extent the shorter branch of 
Cladacanthus, but with the present limited knowledge of the form, being restricted 
to a single specimen, it may not be advisable to remove it. 
_Dipriacanthus stokesu, M‘Coy. 
(Pl. XLVIII., fig. 10.) 
Dipriacanthus stokesii—F, M‘Coy, 1848. ‘“Ann.and Mag. Nat. Hist.,” 2nd ser., Vol. IT.,p.121. 
30 J. Morris, 1854. ‘Catal. Brit. Foss.,” p. 325. _ 
a F. J. Pictet, 1854. ‘Traité de Paléont.,” Vol. IL., p. 292. 
5 5 FE. M‘Coy, 1855. ‘Brit. Paleoz. Foss.,” p. 627, pl. 3 K, fig. 18. 
a 4 Morris & Roberts, 1862. “Quart. Journ. Geol. Soc.,” Vol. XVIII, p. 100. 
A, . J. J. Bigsby, 1878, ‘Thesaurus Devon.-Carb.,” p. 359. 
