TETHYS—-INDIAN OCEAN. 107 
b. Surface marked with ocellated spots, 
lineolata, oculifera, argus. 
bb. Not ocellate. 
c. Mantle with a subcentral tube; swimming lobes am- 
ple. 
d. Olive-brown with pale spots; mantle reddish, 
maculata. 
dd. Dark green, coarsely marbled with dark, and 
with many groups of pale dots, tigrina. 
ce. Characters of mantle unknown, _ tigrinella, nodifera. 
ecc. Mantle with a subcentral perforation; lobes ample ; 
uniform dark green, juliana. 
T. nicRocincra Martens. PI. 17, figs. 14, 15, 16. 
Length, in spirit, 17 mill., alt. 11, breadth 7 mill. Smooth, light 
brown, the free margins of the swimming lobes, the edge of the sole, 
and the margin of the rather large hole in the mantle, black, mostly 
continuous, sometimes rather spotted. 
Shell strongly convex, comparatively large, of a beautiful amber- 
yellow, shining reddish through the mantle; spoon-shaped, with 
shallow sinus and strongly incurved apex; 113 mill. long, 8 wide, 
5 high, occupying more than half the total length of the animal. 
(Martens.) 
Fouquets, Mauritius (Mobius). 
Aplysia nigrocincta MARTENS, in Mobius’ Beitr. zur Meeresfauna 
der Insul Mauritius u. der Seychellen, p. 307, pl. 21, f. 3 (1880). 
“ Reminds one of A. virescens Risso, pl. 19, f. 5, of unknown lo- 
cality, but coloration and form of the shell are different.” This 
species is allied to 7. parvula, T. elongata, ete., species with large 
mantle foramen and very convex shell. 
T. mMacuLaTa Rang. PI. 60, figs. 49, 50, 51, 52. 
Length 9 cm. Oblong, much swollen, depressed at the base, 
elongated in front and obtuse behind, smooth. Swimming lobes of 
moderate size, the dorsal cavity very open. Mantle reddish, with a 
long excurrent siphon and a tubular foramen. Gills roseate. 
Color, externally, brown-olivaceous, with some pale spots, the 
dorsal cavity reddish. 
Shell oval, very concave, membranous with very little calcareous 
substance ; sinus small and,nearly posterior ; apex a little recurved 
