Silurian Fossils of Nova Scotia. 151 



19. Clidophorus subovatus. N. sp. 



Shell, broadly oval or ovate, moderately and evenly convex ; 

 beaks near the anterior end ; umbones moderately elevated ; a 

 scarcely defined depression extending from the umbo towards the 

 postero-basal extremity ; anterior extremity rounded, posterior 

 extremity unknown (? regularly rounded) ; clavicle extending half 

 way from the anterior cardinal margin to the base of the shell. 

 Surface marked by fine unequal sub-lamellose striae. 



This shell is larger and more regularly convex than any of the 

 others here described, and more inequilateral than any except the 

 C, cuneaius. 



20. NucuLiTEs [Orthonota] carinata. N. sp. Fig. 10. 



Shell extremely elongate, nearly three times as long as wide ; 

 sides sub-parallel ; hinge line straight, beaks appressed, sub-an- 

 terior, the anterior extremity rounded ; posterior extremity obli- 

 quely truncate, longer on the hinge line than on the basal margin. 

 Surface marked by a sharp carina which extends from the umbo 

 obliquely to the postero-basal angle, the space anterior to this car- 

 ina marked by distinct elevated lamellose striae, and intermediate 

 finer ones. The space between this and the cardinal line smooth 

 and slightly depressed. Cardinal line anterior to the beak show- 

 ing six or seven crenulations. A strong clavicle extends from the 

 anterior cardinal line with a gentle curve nearly to the base of 

 the shell. 



Fig. 10. Fig. II. Fig. 12. 



This shell presents characters not before observed combined in 

 one species. It has the general form of Ortkonta, while the 

 crenulated cardinal line and the anterior clavicle are characters of 

 Nuculites. The shell is readily distinguished from species of either 

 genus heretofore described. The Orthonotae, yet known, have 

 the surface marking much less sharply defined. 



21. Tellinomya Attentjata. N. sp. Fig. 11. 



Shell elongate, narrow, more than twice as long as high, an- 

 terior end short and rounded, beak elevated, situated a little in 



