82 AMERICAN MARINE CONCIIOLOOY. 



smooth, and covered with a rough, greenish-yellow epidermis; 

 sutnral region depressed and sub-channeled; the spire scarcely 

 prominent above the very huge lower whorl, and placed a little to 



one side; aperture oblique, semicircular. 



Length 5, diam. f. mill. 



New England, 



Genus RISSOA, Frcmenville. 

 Desmarest, Bull. d. Sc, par la Soc. philom., 7. 1814. 

 Cingula, Fleming, Brit. Anim., 297, 305. 1828. 



The animal has large, slender tentacles, with eyes on small 

 prominences near their outer bases; the foot is pointed behind; 

 the operculigerous lobe has a wing-like process and a filament on 

 each side. 



Universal^ distributed, but principally in the north temperate 

 zone. They range from high water to one hundred fathoms, but 

 abound most in shallow water, near the shore, on beds of fucus 

 and zostera. 



1. R. minuta, Totten. Fig. 153. 



I Twbo.) A mir. .J on iii. Science, xxvi. 3G9, f. 7. 1834. 



Shell minute, conic, thin, polished, elevated to an obtuse apex; 

 whorls five, convex, with very fine transverse stripe ; suture dis- 

 tinct, with a round shoulder on the whorl; aperture oval, entire, 

 rounded at the base, very slightly angular above; lip sharp; lower 

 portion of the pillar-lip slightly recurved, with a loosely attached 

 enamel which rises before an umbilical pit; operculum horny, sub- 

 spiral; yellowish-brown, usually covered by a dark green pigment. 



Length 3. 75, diam. 1.5 mill. 



Animal dusky-brown ; tentacles, and a line on each side the 



neck, light drab. Very active in movement. 



Neic England. 



2. K. latior, Mighels and Adams. Fig. 154. 



(Oingula.) Bost. Journ. Nat. Hint., iv. 48, t. 4, f. 22. 1844. 

 Shell minute, ovate-conic, smooth, pale horn-color; whorls more 

 than four, convex; suture much impressed; last whorl broad, 

 larger than the rest of the shell; aperture ovate-orbicular, left 

 margin with a lamina. 



Length 2, diam. 1.25 mill. 



Maine. 



