CLASS PELECYPODA 
77 
The above is the description of Modiolaria disc ors Linnaeus which, 
with Modiolaria laevigata Gray, is the same as M. substriata . I did not 
have access to the latter. The type locality of M. Iccvigata is Greenland. 
Type. Neither the location of the type or the type locality is known to 
the present writer. 
Range. Arctic Ocean to Puget Sound. 
Modiolaria corrugata Stimpson, 1851. 
Plate 14, figs. 8, 9. 
Shells of New England, p. 12. Gould, Invert. Mass.; fig. 84. 
Shell irregularly oval, tumid, heart-shaped when viewed in front, 
bluntly rounded before; hinge margin somewhat ascending and a little 
compressed; at the termination of the ligament the margin gradually 
curves downward so that the shell is terminated behind by a lobular, 
somewhat pointed, tip on a level with the base; basal margin an undulating 
curve nearly parallel with the upper margin; beaks large and prominent, 
not in contact, overhanging the anterior extremity; surface as in M. disc ors; 
but there are sixteen or more ribs in the anterior compartment; those in 
the posterior compartment are more crowded, more distinct, the interven¬ 
ing spaces rounded; and, when viewed under the microscope, the whole 
surface is found to be covered with wrinkles of the epidermis crossing the 
ribs and the spaces between them and also the middle compartment; 
epidermis greenish yellow with clouds of olive. Within silvery, margin 
crenulated by the ribs, and with three or four teeth before the beaks. 
Length, 37; breadth, 20 mm. (Gould, Invert. Mass.) 
Type in Cuming Collection, British Museum. Type locality, Massa¬ 
chusetts. 
Range. Arctic Ocean to Puget Sound. Circumboreal. 
Modiolaria marmorata Forbes, 1838. 
Malac. Monensis, p. 44. Forbes and Hanley, Brit. Moll.; pi. 45, fig. 4. 
Tumid, oblique, usually marbled with colored markings, smooth in 
the middle, rayed with impressed lines at both extremities; beaks quite 
terminal. Length, of an inch; breadth, about five lines. (Forbes and 
Hanley.) 
Type. Neither the location of the type nor the type locality is known 
to the present writer. 
Range. Puget Sound. Circumboreal. 
