26 CONCHOLOGY. 



Shell very thin, conical, tubular, involuted in a spiral manner, 

 loosely and irregularly ; aperture circular, sharp edges, interrupted 

 in the middle by a notch, extending like a slit through the greater 

 portion of its length, and stopping abruptly at some distance from 

 the summit. Inhabits the Indian seas. Eight species. 



Siliquaria anguina. Siliquaria rugosa. 



S. muricata. 'S. terebella. 



S. laevigata. S. lima. 



S. lactsea. S. spinosa. 



FAMILY II. 



Maldaxia. Two Genera. 



1. Genus Clymene. 



Animal. Respiratory organs not determined, supposed to be 

 at the posterir^r part of the body. 



Shell. Tube thin and slender, open at both ends, encrusted 

 externally with sand and fragments of shells. One species. 

 Clymene amphistoma. 



2. Genus JDentalium. PI. V. 



Animal. Body elongated, conical, sub-vermiform, enveloped 

 in a fistula mantle as far as the anterior third, and ending in a 

 bourrelet pierced in its middle by an orifice with fringed edges ; 

 foot altogether anterior, proboscidiform, terminated by a conical 

 appendage, contained in a kind of cup with festooned edges '; head 

 distinct, oval, with a teiYninal mouth in the middle of a digitated 

 lip ; a pair of lateral jaws, formed each of two little oval shells 

 garnished with points. 



Shell. Tubular, regular, symnibtrical, slightly curved longitu- 

 dinally, tapering gradually to the rear, and opening in a round 

 orifice at each end. Inhabits the British seas. Twenty-one 

 species. 



Dentalium elephantinum. Uentalium pseudo-antalis. 



D. aprinum. D. radicula. 



D. sulcatum. D. antalis. 



D= fasciatum. D. arictinum. 



