276 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
of the middle; scarcely elevated; entire surface quincuncially granulated; 
lateral areas scarcely defined, and with the end valves obsoletely subliru- 
late. Interior: posterior valve having 9-10, central valves 1, anterior valve 
10-11 slits; teeth acute; eaves small; sinus wide, short, scarcely laminate. 
Girdle regularly covered with solid, coarsely striated, moderate-sized 
scales. Length, 21; breadth, 15 mm.; divergence, 110°. (Carpenter.) 
(Tryon and Pilsbry, Manual of Conchology.) 
Type in ? Type locality, Monterey, California. 
Range. Prince of Wales Island, Alaska, to San Pedro, California. 
Ischnochiton scabricostatus Carpenter, 1864 
Supplementary Report, British Association for the Advancement of Science, 649. 
Tryon and Pilsbry, Manual of Conchology, 14:121, and 15:76; PI. 16, figs. 55, 56. 
Small, arched, orange; rows of prominent granules over shagreened 
surface. Lobes blunt, slightly rugulose, close to eaves. 8-20 fm. (Car¬ 
penter.) 
Shell small, orange-colored, elevated; valves gothic arched, jugum 
acute. Entire surface very closely granulated; lateral areas well defined, 
with three subobsolete, radiating series of large granules; beaks scarcely 
apparent; umbonal margin slightly turned inward, and having dark spots 
giving a false appearance of teeth. Central areas having separated longi¬ 
tudinal series of narrow, subobsolete riblets, furnished with large granules. 
End valves having similar radiating granulose riblets. Umbo of posterior 
valve scarcely central, little projecting. Interior; sutural plates separated 
by a large flat sinus; insertion plates subobtuse, the end valves having 
10-12, central valves 1 slit; eaves moderate, subconspicuous. Girdle wide, 
closely clothed with imbricating, elongated, transversely striated scales. 
Length, 7 l / 2 ) breadth, A]/ 2 mm.; divergence, 100°. (Carpenter.) (Tryon 
and Pilsbry, Manual of Conchology.) 
Type in United States National Museum. Type locality, Catalina Is¬ 
land, California. 
Range. San Pedro and Catalina Island, California, to Cerros Island, 
Lower California. 
Described as Lcpidopleurus scabricostatus Carpenter. 
Ischnochiton aureotinctus Carpenter, 1892 
Tryon and Pilsbry, Manual of Conchology, 14:123. 
Shell resembling I. scabricostatus, but the lateral areas are scarcely 
defined, radial and longitudinal series of lirae none. Entire surface equally 
granulated. Orange spotted with red. Interior: posterior valve having 11, 
f 878 ] 
