14 
DEVONIAN FAUNA. 
anterior point. Hinge-line apparently about two-tliirds the length of the shell, sunk 
below the angulated superior margin, straight behind the umbo and rapidly 
sinking in front of it. Lunule (?). Escutcheon very large, defined by a sharply 
rounded angle, running straight from the back of the umbo to the postero- 
inferior point, within which it is at first decidedly concave, and then rises to form 
a narrow, flat, obtuse-angled hind wing. Anterior margin narrow, oblique, and 
straight, Antero-inferior point angular. Inferior margin concave in front, and 
then becoming gently convex for the greatest part of its length. Postero -inferior 
point very much produced and very convex. Posterior side rather short, oblique, 
and concave. Back of the shell almost flat except in front, where there is a 
a shallow concavity or constriction ; rounded rapidly over the anterior side and 
post-umbonal angle. Surface covered with between thirty and forty sharp, 
smooth, obtusely angulated, distant ridges, divided by similarly angled grooves, 
without any radiating marks, and following the marginal contour except that of 
the upper margin, by which they are truncated ; these ridges being fine and small 
on the anterior lobe, becoming gradually larger till they pass the post-umbonal 
line, and then becoming suddenly much finer and uniform upon the hind wing. 
Shell-structure thin. 
Size. — Length 17 mm., breadth 11 mm., depth of one valve 3 mm. 
Localities. — There are three specimens from Luramaton in my Collection ; 
another, perhaps from Wolborough, in the Battersby Collection of the Torquay 
Museum ; and another, from Barton, in the Lee Collection of the British Museum. 
Remarks. — This shell appears to have been very fragile, and all the specimens 
I know of it are fragmentary, except the one in the British Museum, which, 
although not so flat, and differing in some other points, I believe to belong to the 
same species, and therefore to enable us to arrive at its true outline. 
From the accompanying forms it is easily distinguished by its flatness, its fine, 
smooth, angulated ribs, and its general contour. 
From C. elongata, d'Archiac and de Verneuil, as given by them^ and by 
Sandberger/ which seems its closest ally, it is separated by its greater flatness, its 
small constricted anterior lobe, its smaller umbo, and its smooth ribs. It is true 
that the former authors do not mention radiations on the ribs of their shell, but 
there is every reason to believe it to be the same species as Sandberger's, on 
which they are noted. 
Sanguinolaria undata, Miinster,^ is rather similar in ornament, but very 
dissimilar in shape, and has clearly no real affinity with it. 
1 184*2, d'Archiac and de Verneuil, ' Geol. Trans.,' ser. 2, vol. vi, pt. 2, p. 374, pi. xxxvi, 
figs. 14, 14 a, b. 
2 1853, Sandberger, ' Verst. Rhein. Nassau,' p. 261, pi. xxvii, figs. 14, 14 a — c. 
3 1840, Muaster, ' Beifcr.,' pt. 3, p. 73, pi. xii, fig. 27. 
