TETHYS-ANTILLEAN. 83 



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 aiphon 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) Morch. 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 



