TETHYS—ANTILLEAN. &3 
ends, distal extremities with the fold short. Tentacles small, conic, 
conspicuously slit. Swimming lobes ample, free, united behind only 
at their union with the foot. Mantle large and convex, smooth, 
with a small central thin-edged perforation. Posteriorly having a 
conspicuous, large excurrent siphon formed by a broad enlargement 
of the free mantle edge. Genital pore under forward right border 
of mantle surmounted by a fleshy prominence. Opening of opaline 
gland large, single, about 12 mill. back of genital pore, and well 
under the gill. Penis, when extended, about 28-30 mill. long, 
swollen at base, then tapering. 
Color deep purple-black, the inside of swimming lobes slightly 
lighter, blotched at the edge with black. Mantle purple-black, 
spotted irregularly and indistinctly with lighter fleshy-purple. 
Shell rounded, very convex, posterior sinus wide, concave; the 
apex well hooked and calloused, the membraneous layer reflexed 
behind it, cuticular layer sepia-brown ; membranous margin wide 
below; calcareous layer rather thin. Length 39, breadth 34 mill. 
Key West, Florida (H.C. Machette). 
This form, which, on account of the general color of the body, I 
at first regarded as a probable variety of Rang’s A. brasiliana, dif- 
fers from that species in the greater proportional size of shell to 
total length of the animal, the maculated mantle and inside edges of 
the swimming lobes, the simple, thin edged mantle foramen (that of 
brasiliana being figured as tubular), and the wider, rounder shell. 
The types are two well preserved alcoholic specimens collected by 
Mr. Machette in 1893. They stain the liquor a dark-smoky yel- 
low. 
T. PARVULA (Guilding) Mérch. PI. 37, figs. 23, 24, 25. 
Flaccid specimen: Body soft, slender, fusiform ; epipodial lobes 
short, entire and continuous behind ; eyes sublateral, in front of the 
bases of the tentacles. Tentacles slender, acute. Length 16 mill. 
(Morch.) 
Contracted specimen : Body leathery, tough, transversely wrinkled 
and grooved ; orifice in the mantle large, oval, and like the borders 
of the epipodial lobes, margined by a black line. Length 12 mill. 
Shell not seen in this specimen, but feels as in the preceding. 
(Morch.) 
Shell small, rather solid, narrowly ovate or piriform, extremely 
convex ; somewhat translucent white or brown tinted, more deeply 
so toward the lower margin. Apex strongly incurved, involute and 
