A DICTIONARY OF TERMS. 



lix 



Sinuous. 

 Sinus. - 

 Siphon. 

 Spine. - 



Spire. - 

 Spiral. 

 Stri^:. - 



Striated, 

 Summit. 



Summit. 



Suture. 



Waved, folded, or deeply lobed. The margin of a 

 shell is sinuous, when it bends in and out. 



A deep cut. The Murex Babylonius has a sinus in 

 the lip. 



A prolonged tube, running sometimes through the 

 partitions of chambered shells. 



A lengthened point either straight or curved. The 

 Thorny Woodcock, Murex Tribulus, has very long 

 spines. 



Each single, or separate turning, or circumvolution 

 in a Univalve shell, is called a spire. 



Univalve shells, having one or more spires, are called 

 spiral. 



Very fine lines, either flat or raised, which cross the 

 surface of shells in different directions. When they 

 proceed from hinge to margin, they are called longi- 

 tudinal striae, and when in a contrary direction, trans- 

 verse striae. Concentric striae are those which form 

 the segments of circles. 



Charged with striae. 



The highest part of a shell. In Univalves it is 

 the point of the spire. 



The upper part of the valves, in Bivalve shells, is 

 called the summit. It is generally curved inwards, 

 towards the hinge, which it surmounts. 



A toothed joint. The valves of some of the Acorn 

 shells are connected by sutures. 



Teeth. ^ - Angular plaits upon the pillar lip of Volutes, and 



some other shells. 

 Teeth. - - Protuberances, and fangs, on the hinges of Bivalve 



shells. 

 Tentacula. Delicate, fleshy bodies, with which animals of the 

 class Mollusca, are provided; they are capable of 

 contraction and extension, and are endued with ex- 

 treme sensibility. The horns of the snail are its 

 tentacula. 



