16 NOMENCLATURE. 



hilaUata. Bilabiate; constructed with both an 

 internal and external lip; in opposition to 

 those shells which arc destitute of the in- 

 terior one. 



dehiscens. (iaping; the lower part of the lip be- 

 ing distended. 



coarctata. Coarctate ; contracted, straight : op- 

 posed to eflfuse. 



ejfusa. Effuse; having the lips separated by a 

 sinus or gutter^ so tliat if the shell were 

 filled with water it would flow out at the 

 back part. 



rejlexa. Rellex ; having the fore ])art of the Up 

 reflected towards the lowest whorl. 



reponda. Spreading ; having broad oj)cn lips. 



resvpinnla. Resujjinate; turned upwards. 



transversa. Transverse; situated in a plane pa- 

 rallel to the inclination of the spiral line of 

 the whorls ; in the direction of that line. 



dentata. Dentate; furnished with teeth. 



Apex. Ari-x, Tii"; sunuuit of the spire. 



decollahis. Decollate ; ajiparently nnitilated, 

 having the spire, or the upper part of it, 

 horizontally cut off. 



