36 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
of the plate in most of the species being turned up like a tooth. The 
cardinal teeth between the ligamentary fossette and the lateral tooth or 
socket vary in form and arrangement in each species. (Dali.) 
Type. Pleurodon ovalis Wood. 
Distribution. California to Gulf of California. 
Subgenus Cyrilla A. Adams, 1860 
Pleurodon munitum (Carpenter) Dali, 1898. 
Trans. Wagner Inst., 3; part. 4: 602. 
In tliis species the fossette has become still larger than in Cyrilla 
sulcata. None of the anterior cardinal teeth is left. The four posterior 
cardinals are of the bent or V-shaped variety, and the cardinal plate and 
shell have become more solid and heavy. The ligament is wholly internal 
and the cardinal plate solid and flat. The wing-like expansions of its 
outer margin, so notable in all true species of Pleurodon are gone. (Dali.) 
Type in U. S. N. M. ? Type locality, off Catalina Island, California. 
Range. Santa Barbara Islands to the Gulf of California. 
Genus MALLETIA Desmoulins, 1832. 
Shell oval, compressed, smooth or concentrically furrowed, epidermis 
olive; ligament external, elongated, prominent; hinge with an anterior 
and posterior series of fine sharp teeth; interior subnacreous; pallial sinus 
large and deep; anterior adductor giving off a long oblique pedal line. 
(Tryon. S. S. Conch.) 
Type. Malletia norrisii (Sby. )~chilensis Desm. 
Distribution. United States, Valparaiso, New Zealand. 
Range in Time. Miocene, Patagonia. 
Malletia talama Dali, 1916. 
Proc. U. S. N. M., 52:400. 
Shell large, thin, plump, of a uniform oval, with a brilliant, smooth 
light yellowish-olive periostracum; beaks low, near the anterior third with 
about 8 V-shaped teeth in front of them; on the hinge line and about 36 
much smaller teeth behind them; the latter are not obviously V-shaped, 
are very uniform in size and appearance; the hinge line is thickened under 
the anterior teeth, but the ligament is strictly external. The shell is slightly 
wider and more compressed behind but the difference is very small. 
Length, 23; height, 15; diameter, 10 mm. (Dali.) 
. Type in U. S. N. M., No. 225384. Type locality, Station 3603 off 
Pribiloff Islands, Bering Sea, in 1771 fathoms. 
Range. Bering Sea to Oregon. 
