16 
DEVONIAN FAUNA. 
having a blunt keel surrounding the area as in our shell, but as having a distinct 
lunule, which our shell has not. 
Affinities. — Thetis (?) trigona, F. A. Romer/ seems from the description to 
have a similar truncated area, but it differs in its general shape, being more 
transverse and much less produced anteriorly. 
3. Genus. — G-qnigphora, Phillips, 1848. 
Shell transversely oblique, equivalve, very inequilateral. Umbo recurved, 
proximate, anterior, arching forward, very much compressed, so as to form a sharp 
elevated keel, which runs down the centre of the back to the base. Hinge-line 
nearly straight, bearing on the left valve a long oblique tooth between two grooves, 
angulated at its extremities. Surface covered with concentric ornament. Lunule 
small, deep. 
Phillips named his genus without description. It is generally referred to the 
Cyprinidge. The general external resemblance of the fossil described below to the 
type species Goniophora cymboeformis, Sowerby, sp.,' makes me believe that it 
must belong to the present genus. At the same time the only figures of the hinge 
which I have been able to find are some given by Hall, who classes it under the 
Mytilidse, and these are so different as to cause doubt whether the American 
forms have any real kinship to the present shell. 
This genus has been described from the Silurian and Devonian formations. 
1. GONIOPHOEA OBLiQUA, Whidhovue, sp. PL III, figs. 1, 1 d, 1 h. 
1841. Megalodon caeinatum, Phillips (not Ooldfuss). Pal. Fos., p. 136, pi. Ix, 
figs. 60* a, h. 
1854. Megalodon caeinattjs (not Ooldfuss), Morris. Catal. Brit. Foss., p. 209. 
1888. — — Etheridge. Foss. Brit., vol. i, Pal., p. 161. 
1889. — OBLiQUUS, Whidborne. Greol. Mag., dec. 3, vol. vi, p. 78. 
Description.— heit valve large, oblique, deep, subquadrate or rhomboidal. 
Umbo large, prominent, elevated, oblique, proximate, incurved, and facing 
anteriorly, situated about the centre of the hinge-margin, compressed laterally so 
as to form a sharp erect keel, which is continued in a slightly curving line to the 
inferior point, and which gradually becomes more rounded and stouter in that 
direction. Hinge-margin rather short, nearly straight, terminated by an angle 
of about 60° in front, and by a very large angle behind. Anterior margin very 
1 1843, F. A. Eomer, ' Verst. Harzgeb.,' p. 26, pL vi, fig. 25. 
2 1839, Sowerby, in ' March. Sjat. Sil.,' p. 602, pi. iii, fig. 10, and pi. v, fig. 6. 
