208 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Genus CYRTODARIA Dauclin, 1799. 
Shell oblong, gaping at each end; posterior side shortest; ligament 
large and prominent; hinge thick, without teeth; epidermis black, extend¬ 
ing beyond the margins; anterior muscular scar long, pallial impression 
irregular, slightly sinuated. (Tryon. S. S. Conch.) 
Type. Cyrtodaria siliqua Daudin. 
Distribution. Arctic Seas, Cape Perry, Northwestern America, 
Newfoundland. 
Cyrtodaria kurriana Dunker, 1862. 
Malak. Blatt., p. 38, 1861. 
Testa lineari-oblonga, recta, tenuisculpta, postice valde hians concen- 
trice striata obsoleteque plicata, epidermide cornea fusco-variegata ob- 
ducta; umbones parum prominentes decorticati, submediani. Long., 35; 
alt., 40; crass, .28 mm. (Dunker.) 
Type locality, West Coast of Greenland. 
Range. Arctic Ocean and south to Norton Sound, Alaska. Also 
Greenland. 
Genus SAXICAVA Fleuriau, 1802. 
Shell when young symmetrical, with two minute teeth in each valve; 
adult rugose, toothless; oblong, equivalve, gaping, ligament external; 
pallial line sinuated, not continuous. It is found in crevices of rocks and 
corals, and amongst the roots of seaweed, or burrowing in limestone and 
shells. (Tryon. S. S. Conch.) 
Type. Mytilus rugosus Linnaeus. 
Distribution. Arctic seas, where it attains it largest size, Mediter¬ 
ranean, Canaries and the Cape. 
Range in time. Pleistocene and Miocene of Europe and United 
States and in all glacial deposits. 
Saxicava arctica Linnaeus, 1767. 
Plate 9, fig. 6, and plate 51, fig. 4. 
Syst. Nature, ed. 12, p. 1113. Conch . Iconica; pi. 1, fig. 1. 
Shell oblong, rugose, thick posteriorly, spiniferous when young, with 
two teeth on the hinge; without teeth on the hinge when adult; anterior 
side narrow, short; ventral margin sinuous; umbos depressed, anterior; 
posterior side broader, square, biangular, broadly truncated. (Conch. 
Iconica.) 
Type in British Museum. Type locality, Arctic. 
Range. Arctic Ocean to Panama. Also Atlantic. 
