1 6 NOMENCLATURE. 



bilabiata. Bilabiate; constructed with both an 

 internal and external lip ; in opposition to 

 those shells which are destitute of the in- 

 terior one. 



dehiscens. Gaping; the lower part of the lip 

 being distended. 



coarctata. Coarctate ; contracted, straight : op- 

 posed to effuse. 



effusa. Effuse; having the lips separated by a 

 sinus or gutter, so that if the shell were 

 filled with water it would flow out at the 

 back part. 



reflexa. Reflex; having the fore part of the lip 

 reflected towards the lowest whorl. 



repanda. Spreading ; having broad open lips. 



resupinata. Resupinate; 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. 



dent at a. Dentate; furnished with teeth. 



Apex. Apex, Tip; summit of the spire. 



decollatus. Decollate; apparently mutilated, 

 having the spire, or the upper part of it, 

 horizontally cut off. 



