84 DEVONIAN FAUNA. 



Description. — Shell obliquely convex, very transverse, of moderate size. Umbo 

 situated at about the anterior third of the length, small, much flattened and 

 truncated, incurved, tending forward. Hinge-line probably nearly the length of 

 the shell. Anterior margin produced, narrow, evenly convex. Inferior margin 

 very long, nearly straight, slightly oblique. Posterior margin broad, gently 

 convex. Contour of back gently convex on the line of greatest depth from umbo 

 to postero-inferior corner, in front of which it is obliquely flat, and behind which 

 it is gently convex. Surface with a few rather irregular and divaricating, rounded 

 growth-ridges on the back, which almost vanish on and behind the aforesaid line. 



Size. — Height 10 mm., length 24 mm. 



Locality. — There are three specimens from " the top of the Baggy Stage," S.W. 

 of Sloly, in the Woodwardian Museum. 



BemarJcs. — These shells are very indistinct, but they appear so closely to 

 correspond with the figures given by Hall of his Sphenotus solenoides, that there 

 seems great probability that theyare identical. Our best preserved specimen (fig. 10) 

 appears still more transverse, but this is evidently due to the squeezing to which 

 the beds have been so much subjected, and possibly the greater flattening and 

 depression of its umbo may be due to the same cause. The posterior ridge or keel 

 seems sharper in the American shell, and the inferior margin sometimes slightly 

 concave. 



3. Sphenotus? solenifoemis, Goldfuss, sp. Plate XII, figs. 1, 1 a. 



1834-40. Sanguinolabia soleniformis, Goldfuss. Petref. Germ., vol. ii, p. 277, 



pi. cliii, fig. 7. 

 1895, Sphenotus solenifoemis, JBeushausen. Abhandl. k. Preuss. Landes., n. s., 



pt. 17, p. 215, fig. 19; and 

 pi. xviii, figs. 1, 2. 



Description. — Shell (cast) rather large, extremely transverse, subconvex, 

 quadrate. Umbo flattened, adpressed, proximate, curved forward, and situated at 

 about the anterior tenth of the length. Hinge-line straight, about five-sixths the 

 length of shell. Anterior margin probably sloping obliquely from umbo to the 

 anterior angle, which is one-third way down, and then becoming obliquely convex. 

 Inferior margin very long, direct, straight. Postero-inferior corner rather pro- 

 duced, apparently deeply convex. Posterior margin very short, slightly convex 

 and oblique. Contour of back rounded in front, slightly concave beneath umbo, 

 and with a blunt keel running from behind umbo in a slight curve to postero- 

 inferior corner. Posterior slope flat and oblique, and marked with a few strong 



