PLEUROTOMA. 389 



short, cylindrical, and diverging, with blunt tips ; they are 

 somewhat curved and resemble the prongs of a dung-fork : 

 eyes none, nor any eye-stalks : foot long and slender, truncated 

 in front, and obtuse-angled behind : sole broad : verge falcate, 

 on the right hand : [odontophore composed of thin and some- 

 what curved spine-shaped pleurae, with a large head which is 

 excavated or gapes on the lower side. (Loven.)] 



Shell elegantly spindle-shaped, attenuated towards each 

 end, the axis or greater diameter being nearer the base and 

 formed of the upper portion of the body- whorl ; it is of a deli- 

 cate and rather thin texture, semi transparent, and not gloss}- : 

 sculpture, numerous oblique longitudinal ribs, which are plait- 

 like and slight on the lower two whorls (nearly wanting on the 

 last), more prominent and nodulous on the upper whorls ; they 

 neither extend to the base nor to the suture, and occupy only 

 the middle portion of each whorl; the whole surface (except 

 the apex, which is quite smooth and glossy) is covered with 

 fine and close-set spiral striae, some of which on the body- 

 whorl alternate in size ; lines of growth microscopic and flex- 

 uous ; colour uniform milk-white : spire gradually tapering to 

 a blunt point : ivliorls 10, convex, somewhat angulated in the 

 middle, and compressed or slightly excavated below the suture ; 

 the last whorl occupies about one-half of the shell: suture 

 shallow : mouth of an irregular shape, long and narrow, acute- 

 angled above ; length nearly one-third of the shell : canal 

 rather short, but slender, very wide and open, bending a little 

 to the left, and ending in an obliquely curved notch: outer Up 

 rounded from the labial notch to the base, with a thin and 

 even edge : labial notch broad, deep, and remarkably distinct ; 

 it is placed considerably below the junction of the outer lip 

 with the periphery : inner lip consisting of a thin glaze or 

 polish, which is spread over the pillar ; its limit is coextensive 

 with the outer lip : pillar broad and flexuous : operculum pear- 

 shaped, having the point or nucleus at the base on the inner 

 side ; it is rather small, ambercolour, and marked with ellip- 

 tical lines of increase, like the valves of a Pinna. L. 085. 

 B. 0-25. 



Habitat : Fine muddy sand, east of Shetland, in 78 f. : 

 apparently very rare : for several dredging-voyages which 

 I have made in these seas yielded only one live and three 

 dead specimens. Its discoverer, Professor Loven, re- 



