22 



INTRODUCTION. 



papillary apex is one which is swelled at the extremity into a 

 litttle rounded knob, or nipple ; and a mammellated apex is 

 one which is rounded out more fully. 



Whorls. 



The spire is described as consisting of numerous or few 

 whorlsj and sometimes the number of them is particularly 

 stated. A whorl consists of one turn of the spiral cone. The 

 whorls are described as flattened, when their sides are not 

 much bulged out: when the contrary is the case, the 

 whorls are said to be ventricose, and either rounded or 

 angulated. The degree of rapidity with which the whorls 

 become enlarged presents an important source of distinction. 

 The suture, or seam, which separates one whorl from another 

 is also noticed as being distinct or otherwise ; canaliculated, 

 or grooved ; or covered by an enamel, which in some instances 

 is even tumid or swelled into a ridge. 



Fig. 33,/ew; 34, immerous ; 35, rounded, ventrieose; 36, angular, ven- 

 tricose ; ^7, flattened. 



Suture. 



Fig. 38, canaliculated ; 39, enamelled. 



