484 CONIDiE. 



intervals are concave, and broader than the costse them- 

 selves. The whorls are high, and of moderately fast longi- 

 tudinal increase ; they are well defined by a rather 

 slanting simple but very deep suture. The spire, which 

 is composed of eight coils, usually exceeds, and always vies 

 with the length of the body ; its apex is finely pointed. 

 The whorls do not taper above, the gradual diminution of 

 breadth in the spire being effected by the narrowing 

 throughout of each successive coil ; they assume, too, a 

 slightly subscalar appearance from the circumstance that, 

 although not at all ventricose in the middle, they bend in 

 a little both above and below. The body is rather narrow, 

 and is somewhat quickly attenuated to a moderately acute 

 basal extremity. The narrow mouth, Avhich is nearly as 

 broad below as above, occupies from scarcely two-fifths 

 to three-sevenths at utmost, of the ventral length ; its 

 contraction is scarcely so great as in costata, since the 

 external rib that thickens the outer lip of that species is 

 broader than in the present shell. The outer lip, after its 

 slightly abrupt projection, and not very conspicuous poste- 

 rior sinus, is at first nearly straight, and then continuously 

 curves inwards in a moderately convex line. The pillar 

 lip, which, as well as the throat, is devoid of sculpture, is 

 white, and nearly straight. Our largest example is rather 

 more than eight lines long, and about two lines and a half 

 broad.* 



We have never seen the animal of this species. Mr. 



* The P. costulatum of Philippi (Moll. Sicil. vol. ii. p. IGG), and Kiener 

 (Coq. Viv. Pleur. p. 78, pi. 25, f. 2), approaches very closely to our shell, and 

 Middendorff's description of it (Mai. Rossic. pt. ii. p. 117) agrees fairly 

 enough ; as, however, the characters ascribed to the original Mangelia costidata 

 of Risso (H. N. Europe Merid., vol. iv. p. 219) do not sufficiently correspond to 

 those of the British sj)eci('s, we have not ventured to cite those references in our 

 synonymy. The P.coiUdcUa of Cantrainc (Bull. Brux. 1839) is not our species 



