294 POPULAR CONCHOLOGY. 



Base. The extremity opposite to the Apex, in Uni- 

 valves : in such Bivalves as adhere to other sub- 

 stances by one of their valves, as in Spondylus, 

 Anomia, &c, that valve is termed the basal. 



Bicarinated. Having two elevated or sharp ridges. (See 

 Carinated.) 



Bicornute. Like, or having two horns. 



Bifid. Cleft in two. 



Boss. The projecting point in each valve, near the hinge 

 in Bivalves ; the commencement of the shell. 



Byssus. A bunch of silk-like fibres, by which many spe- 

 cies of Bivalves are attached to other substances. 



Callosity. A thick mass of shelly matter. 



Canal. A groove or gutter observable in different parts 

 of certain spiral shells belonging to the Zoophaga, or 

 carnivorous tribe. In these the canal is either 

 lengthened, as in Murex, short, as in Harpa, or trun- 

 cate, as in Buccinum : in the two latter it thus gives 

 place to a notch, but in all these instances, it is that 

 part fitted for the protrusion of the long cylindrical 

 siphon possessed by all these animals. 



Cancellated. When the surface is marked by striae or 

 lines, which cross each other at right angles. 



Cardinal Teeth, in Bivalves, are those placed immediately 

 beneath the bosses, and between the lateral teeth, 

 where such exist, as in the common Cockle. 



Carinated. Ridged like the keel of a boat. 



Cartilaginous. Gristly, like a tendon. 



Chambered. Divided internally into compartments, as in 

 the testaceous Cephalopoda, or Nautilus. (Polytha- 

 lamous?) 



Columella (or Pillar). The internal support of most 



