SOLEMYIDZ. 223 
(Solemyacea.) 
Famity SOLEMYID#. 
Shell elongated, transverse, equivalve, regular, very inequi- 
lateral, gaping, thin, covered (in Solemya, the recent genus) with 
a thick epidermis, extending beyond the shell-margins as a fringe ; 
hinge toothless ; ligament inserted in an oblique process and 
hidden; pallial line simple. Along with Solemya have been 
associated a number of fossil forms agreeing generally in the 
shape of the shell, yet by no means of certain relationship with it. 
Sotemya, Lamarck, 1818. 
Syn.—Solenomya, Menke, 1828. Janeira, King. 
Distr.—6 sp. United States, Canaries, West Africa (Gaboon 
River), Mediterranean, Australia, New Zealand ; burrowing in 
mud; 2 fathoms. Fossil,4 sp. Carb.—; Britain, Belgium. 
2 Cret. sp.; N. America. S. Australis, Lam. (cxxiii, 63). 
Shell elongated, cylindrical, gaping at each end; epidermis 
dark, horny, extending beyond the margins; umbones posterior; 
hinge edentulous; ligament concealed; pallial line obscure. 
Outer layer of long prismatic cells, nearly parallel with the 
surface, and mingled with dark cells,as in Pinna; inner layer 
also cellular. 
Animal with the mantle-lobes united behind, with a single 
siphonal orifice, hour-glass shape, and cirrated ; foot proboscid- 
iform, truncated and fringed at the end; gills forming a single 
plume on each side, with the lamine free to the base; palpi long 
and narrow, nearly free. 
CuinopistHA, Meek and Worthen, 1870. 
Distr.—C. antiqua, Meek (cxx, 16,17). Devon.; Ohio. C. 
radiata, Hall. Carb.; Ills. 
Shell transversely oval, very thin, rather ventricose, equivalve, 
very inequilateral; beaks near the posterior extremity and 
directed backward, that of the right valve with its immediate 
apex curving under the beak of the left, which seems to be a 
little excavated for the reception of the same; ligament external, 
short, rather prominent, and occupying an oval or lance-oval 
shallow cavity, formed by the slight inflection of the margins of 
the valvesimmediately behind the beaks; valves with their margins 
smooth within and closed all around; hinge apparently edentu- 
lous ; surface smooth, with growth-lines and sometimes traces 
of fine radiating lines; muscular impressions shallow; pallial 
line slightly marked, without sinus. 
Differs from Solemya in its short gibbous form, want of internal 
ridge, closed margins, entirely external ligament, ventricose beaks, 
and their posterior position. 
