292 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Type in United States National Museum. Type locality ? 
Range. San Diego, California, to San Ignacio Lagoon, Lower Cali¬ 
fornia. 
Genus CALLISTOCHITON Carpenter, 1882 
Valves conspicuously sculptured; the insertion-plates short, smooth or 
nearly so, festooned, being curved outward at the ribs and slit there, 
thickened outside at the edges of the slits, the latter corresponding in 
position to the ribs of the outer surface. Sinus squared. Mucro median 
or post median, generally depressed. Girdle poreless, densely clothed with 
minute striated or smooth scales. (Tryon and Pilsbry, Manual of Con¬ 
eirology.) 
Type. Chiton pulchellus Gray. 
Distribution. Australia, Red Sea, Japan, Gulf of Mexico and west¬ 
ern Americas from southern California to northern Chile. 
Callistochiton palmulatus Carpenter, 1892 
Tryon and Pilsbry, Manual of Conchology, 14:262; PI. 58, figs. 12-16. 
Shell similar to C. pulchellus, but more flattened, the dorsal ridge acute; 
mucro subcentral, depressed, the posterior area strongly swollen; sculpture 
stronger; central areas having about 10 sub-parallel acute lirae on each 
side, pectinating the sutures, interstices deeply punctate. Anterior valve 
having 11 ribs, of which the outer two are joined; posterior valve 7 very 
strong ribs bifurcating behind. Interior: anterior valve having 11 slits, 
central 1, the teeth normal; posterior valve having 26 slits, the teeth 
crowded, minute, palmate. Eaves very strong; sinus small, strongly lami¬ 
nate, the laminae deeply slit on each side. Girdle imbricated with striated 
scales. Length, 11%; breadth, 7% mm.; divergence, 135°. (Carpenter.) 
(Tryon and Pilsbry, Manual of Conchology.) 
Type in California State Collection, No. 1077. Type locality, Santa 
Barbara, California. 
Range. Monterey, California, to San Marco Island, Lower California. 
Callistochiton palmulatus mirabilis Pilsbry, 1892 
Tryon and Pilsbry, Manual of Conchology, 14:263; PI. 58, figs. 7-11. 
Shell oblong, elevated, the back angular, side-slopes convex. Surface 
lusterless, dull brownish, the lateral areas and end valves blackish. Valves 
not beaked; the lateral areas widely separated by the eroded beaks, greatly 
elevated, each split by a deep median sulcus, the two ribs thus formed 
bearing coarse transverse grains. Central areas sculptured with about 15 
[894] 
