fea Neri us. 
VOTER Xe, SEPTEMBER, 1896. No. 5 
NOTES ON SOME WEST AMERICAN CHITONS. 
BY H A. PILSBRY. 
ii. 
Among some interesting small Chitons from San Pedro, Califor- 
nia, collected by Mr. T. S. Oldroyd, which I have lately examined 
(through the kindness of Dr. Dall), the following call for especial 
notice, as they offer differences from the types figured in the Manual 
of Conchology. 
Mopalia imporcata Cpr. 
The single specimen measures 9 by 18: mm., and is somewhat 
more elevated than the type of the species; color pale olivaceous, 
white towards the girdle, speckled on the ribs of lateral areas with 
brown, and with a brown patch on each pleural tract. The teeth 
are very distinctly thickened along the outer edges of the slits, as in 
the typical Callistochitons. Sculpture typical. 
The color is different from that of the type, and the specimen is 
larger. 
Ischnochiton scabricostatus Cpr. 
Lateral areas with four (on one side of valve ii, five ; on one side 
of valves iv and vy, three) radial riblets, which are very weakly, 
hardly perceptibly, granose. Sutures very feebly crenate. Anterior 
and posterior valves with 9 slits each. Color reddish (but not at 
all of an orange cast), with a few inconspicuous white spots on 
some of the lateral areas. 
