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MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
SECTION NEAPLYSIA Cooper, 1863 
Tethys californica Cooper, 1863 
Proceedings of the California Academy of Sciences, 3:57; fig. 14. 
Shell contained in the substance of the mantle cartilaginous, translucent, 
trapezoidal or hatchet-shaped, margins rounded, slightly convex above, 
the nucleus or center in old specimens distant from the posterior end or 
apex. Faint radiating lines diverging from the nucleus, crossed by an 
irregular network of darker lines, all ending abruptly at some distance 
from the margin, which has thus a wide, nearly transparent border. An 
accessory plate arises on the inner surface from the nucleus, spatulate in 
form and slightly raised. (Cooper.) 
This was described as Aplysia calif ornica Cooper. Form and external 
appearance as usual in the genus. Length, 15; breadth, 5 in.; height 
about the same. Color pale gray or greenish, becoming purplish on the 
side folds of the mantle with scattered white specks from which an 
irregular network of brown lines extends over the rest of the body, inter¬ 
spersed with large brown blotches. Inner surface of mantle varied with 
alternating painted bars of white and dark brown interlocking together. 
Sole of foot black. Eyes very minute and black. (Cooper.) 
Type in California State Collection, species 1045. Type locality, San 
Pedro, California. 
Range. Monterey to San Pedro, California. 
Tethys ritteri Cockerell, 1901 
Nautilus, 15:90. 
Length, 21 cm.; breadth, about 8 cm. Dark grayish-olivaceous; sides 
with oblique, flame-like, blood-red markings, especially about the middle 
of the body; upper surface of the head and outer surface of epipodial 
lobes mottled with brown, but without any conspicuous blotches; inner 
surface of epipodial lobes and mantle covering shell pale sea-green, wholly 
without markings; lobe overlapping branchiae deep rich purple; when the 
shell is removed, the area beneath it is seen to be strongly suffused with 
dark purple; branchiae purplish-gray; sole 45 mm. broad, transversely 
grooved and corrugated, grayish-brown, inclining to coffee-color; epipodial 
lobes about 80 mm. long and 28 broad, from base within ends of lobes 
to nearest part of sole about 67 mm.; anterior tentacles 11 mm. from 
inner base to tip; posterior tentacles 14 mm. long. 
Shell very thin, flexible, corneous, 58 mm. long; 42 broad; accessory 
plate well-developed. The animal produces an abundance of a reddish- 
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