22 



INTRODUCTION. 



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

 little rounded nob, or nipple ; and a mammellated apex is one 

 which is rounded out more fully into the shape of a teat. 



Whorls. 

 The spire is described as consisting of numerous or few 

 whorls, 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 the sides are not 

 bulged out so as to cause the outline of the spire to deviate 

 considerably from straightness : 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 distinc- 

 tion. The suture, or seam, which separates orie whorl from 

 another is also noticed as being distinct 'or otherwise ; 

 canaliculated, or grooved; or covered by an enamel, which in 

 some instances is swelled into a ridge or tumid. 



Fig. 3'6,/eto ; 34, numerous; 35, rounded, ventricose ; 36, angular, ven- 

 tricose ; 37, flattened. 



Suture. 



yiiii[\\ 



39 28 



Fig. 38, canaliculated; 39, enamelled. 



