1 
SYNOPSIS OF GENERA. 
The species of this genus apparently constitute a very natural group, since 
they present such characteristic features of form and surface characters. 
These shells have sometimes been referred to Modiomorpha and to Sanguinolites, 
but they are clearly distinct from either, and cannot be properly referred to any 
previously established genus. 
Some of the species in their natural condition have had considerable con¬ 
vexity, or even gibbosity, in the umbonal region; but they are evidently thin 
shells, and usually much compressed. The shell rarely preserves evidence of 
radiating striae, which are scarcely superficial. 
Examples: Glossites teretis, pi. xcvi, fig. 15. 
Glossites lingualis, pi. xl, figs. 16, 17 ; pi. xcvi, figs. 9-11. 
Glossites ellipticus, pi. xcvi, fig. 8. 
Elymella, n. gen. [Type, Elymella nuculoides, Hall.] 
Shell equivalve, inequilateral, ovate-elliptical. Anterior end very short and 
the margin rounded. Posterior end narrower and rounded at the extremity. 
Beaks closely incurved; umbo prominent. Cardinal line short. Umbonal 
slope prominent in the upper part, not defined and merging into the general 
convexity of the shell. 
Surface marked by fine concentric striae of growth, which are sometimes 
lamellose and elevated into concentric ridges. 
Hinge-line short, the internal characters undetermined. Muscular impres¬ 
sions unknown. 
The small group of shells here termed Elymella cannot, with propriety, be 
referred to any established genus, and therefore this name has been chosen in 
reference to the form and expression of the fossils. The form of the shell and 
the direction and character of the concentric striae resemble some species of 
Nucula ; but although occurring with specimens of the latter genus showing the 
hinge teeth, none of the specimens of Elymella have preserved any indication of 
such characters. 
Examples: Elymella fabalis, pi. xl, figs. 5, 9. 
Elymella nuculoides , pi. xl, figs. 6, 7, 8. 
