33 DENTALIUM. TOOTH-SHELL. 



shape form, being full two tenths of an inch wide at the 

 larger end, and tapering to hardly the twentieth part of an 

 inch at the smaller end, which terminates in a small circu- 

 lar perforation; the striae are also much finer, double the 

 number of our present species, and stronger at the pointed 

 end, whence they gradually lessen, so as to become hardly 

 visible at the larger end. Our present shell, which is hot 

 uncommon on the western coast, tapers very little, and has 

 the striae equally strong throughout, v. v. 



4. Dentalium striatulum. Striated Tooth-shell 

 Lister, pi. 547. f. 1, lower fig. 



Dentalium octangulum. Donovan, pi. 162. 



Shell slender, tapering to a fine point, slightly Curved, 

 semitransparent, open at both ends, with eight longitudinal 

 angular ribs, between each of which are three or four very 

 obtuse longitudinal striae : color greyish-white, pale rufous, 

 or green with a white tip : length about two inches. 



Cornish and Devon coasts : very rare. v. m. 



5. Dentalium labiatum. Proboscis Tooth-sfall. 



Shell nearly cylindrical, very slightly tapering and 

 curved, semitransparent, ivory white, covered when fresh 

 tilth a black glossy skin, most finely and minutely striate 

 longitudinally, open at the larger extremity, the smaller 

 end truncate, with the flattened surface somewhat undu^ 

 lated in a radiate manner and finely striate circularly, from 

 the centre of which projects an oval transparent process 

 or lip terminating in an oval aperture, one side of which is 

 cloven half way down : length an inch or rather more j 

 breadth at the open end two tenths of an inch. 



A few specimens of this species have very lately been 

 brought to us alive, taken by the trawl at Torbay : the ani r 

 mal is cylindrical, white, with a small central tube at the 

 larger end, and a spoon-shaped mouth at the other, v. u. 



6. Dentalium politum. Polished Tooth~shell. 



Shell somewhat cylindrical, slightly tapering and a little 

 curved, semitransparent, quite smooth and finely polished^ 

 white with generally some irregular grey circular bands 

 which* grow darker and more combined together towards 

 the narrower extremity, open at both ends $ the smaller end 



very 



