296 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
teilweise entsprechen. Die Randschuppen sind etwas 180" bret, meist mit 
6 flachen Rippeb besetzt. (Theile.) 
Type in Berlin? Type locality, San Diego, California. 
Range. Known only from type locality. 
Callistochiton acinatus Dali, 1919 
Proceedings of the United States National Museum, 55:510. 
Chiton small, yellowish-white, strongly sculptured; the anterior valve 
with nine nodulous ribs with narrower interspaces, a minutely granulose 
surface and about 12 inconspicuous slits; posterior valve with 18 slits and 
6 nodular ribs; this valve is much smaller, the central tract is narrow and 
coarsely reticulate; intermediate valves somewhat mucronate with one slit 
at each end; the sculpture on the lateral areas consists distally of two very 
prominently pustulate ribs, toward the dorsal ridge there are only crowded 
minor postules; the jugal and pleural tracts are coarsely reticulate, the 
interspaces deep; the girdle yellowish with densely crowded microscopic 
imbricating scales; length, 6; breadth, 3; height, 1.5 mm. (Dali.) 
Type in United States National Museum, No. 218773. Type locality, 
San Pedro, California. 
Range. Known only from the type locality. 
Callistochiton celetus Dali, 1919 
Proceedings of the United States National Museum, 55:510. 
Chiton of moderate size, pale brownish, with a mottled white and 
brownish girdle scaled like the preceding species (C. acinatus ) ; anterior 
valve with 11 nodulous ribs, which, except the closer set posterior pairs, 
have about equal interspaces; this valve has 9 slits, each corresponding to 
a rib, the posterior valve has 24, but only 6 ribs which are mostly split for 
a short distance distally; this valve is conspicuously convex, with about 6 
large smooth nodules to each rib, the central tract is narrow and coarsely 
axially threaded; in the intermediate valves with 1 slit at each end, the 
lateral areas comprise two strong ribs with vertically compressed nodules, 
8 or 10 to a rib, there is a very narrow smooth spot on the hardly mucro¬ 
nate jugum, the pleural tracts have near the jugal area 6 or 7 close-set 
axial threads and beyond them about the same number of sharp straight 
axial threads with wider interspaces crossed by much finer, closer, trans¬ 
verse threadlets; internally the valves are whitish and the sutural laminae 
appear to join each other in front of the obsolete sinus. Length, 10; width, 
6; height, 2 mm. (Dali.) 
[898 ] 
