28 



INTRODUCTION. 



Outer Lips. 



Fig. 25, Helix, reflected; 56, Cyprsea, involute, denticulated ; 57, Seraphs, 

 alated ; 58, Murex, digitated; 59, Rostellaria, dentated. 



The zrcrcer lip, sometimes named the columellar lip, or 

 " labium," is subject to similar variations as to thickness, 

 dentition, &c. That portion of it which lies upon the body- 

 whorl is frequently distinguished from that which intervenes 

 between it and the notch or canal. De Blainville, restricting 

 the term lip " bord gauche" to the former portion, applies the 

 term " columella" to the latter; and in some instances this 

 may be the more convenient method of describing the part in 

 question. The columellar lip is sometimes detached entirely 

 from the body of the shell, as in Murex haustellum ; in others 

 it is decumbent, or lying over the last whorl, although quite 

 distinct, and in some cases, thickened, callous, or tumid. 



At the lower or anterior part, sometimes called the columella, 

 there are in many instances flattened, laminated folds ; these 

 are particularly conspicuous in the genera Cymba and Melo, 

 where, being obliquely spiral and laminar, they are extremely 

 elegant, presenting to the eye graduated repetitions of the line 

 of beauty. In other cases, as in the Turbinellee, they are 

 more horizontal and thickened. 



