NOTARCHUS. 143 
In breathing, the mantle cavity is very forcibly expanded and con- 
tracted. The snail emits an intensely cobalt-blue liquor, part of 
which sinks to the bottom, staining the white coral-sand blue; the 
rest dispersing in the water. (Mobius). 
N. quercinus Gould. PI. 29, fig. 44. 
Length 32 inches. Body limaciform, elongated, delicately attenu- - 
ated ; the ground color slaty, tinted with wood-color, and longitu- 
dinally grained with numerous unequal, rusty lines or folds. Ten- 
tacles very long, linear, truncate at tip, and beset with numerous 
acute papille, The papilla on the body are long and branching 
but becoming more and more simple towards the margin and tail. 
Kyes distinct, in front of the cervical tentacles. (Gd.). 
Levuka, Fiji Is. 
Stylocheilus quercinus Gup., U. S. Expl. Exped., Moll., p. 226, pl. 
16, f. 271 (1852); Otia Conch., p. 227. 
The peculiar coloration and graining of this animal are something 
like that of oak wood. 
N. rurus Quoy & Gaimard. PI. 16, fig. 7. 
This very small species has the body and neck elongated, as well 
as the four tentacles; the foot is quite short. The back appears 
elevated by the dilation of the borders of the pleuropodial lobes. All 
of these parts are villose and of a reddish brown color, with the ap- 
pearance of longitudinal striz. The integument is largely spotted 
with an almost black brown, fading to smoky in front. Genital 
furrow black, and a similar line is on the opposite side. Sole of the 
foot is a very light red-brown. 
Road of Umata, Island of Guam, in 14 fms. (Astrolabe). 
Aplysia rufa Q. & G., Zool. Astrol., ii, p. 314, pl. 24, f. 7. 
The long, filament-like tentacles render it likely that this species 
is a Stylocheilus ; but no labial processes are mentioned by Quoy. 
N. tonaicaupa Quoy & Gaimard. PI. 29, figs. 41, 42, 43. 
Length 63 mill. Animal swollen, full and oval, the anterior por- 
tion elongated, head small; the posterior lengthened and acute. 
Integument green, with spots of varied red and blue. Dorsal open- 
ing small, a little posterior, and oblique. Foot very narrow (Rang). 
Near New Guinea, on free-floating Fucus. 
