XXIV EXPLANATION OF TERMS. 



Retuse. Bending a little backwards. 



Revolute. Folded or rolled a little outwards. 



Semitransparent. Not perfectly transparent, nor quite opake. 



Serrate. Notched like the teeth of a saw. 



Spatulate. Shaped like a spatula or battledore. 



Species. The individual of a family or genus, and distin- 

 guished from all others of its tribe by permanent marks, called 

 specific characters. 



Spire. The body of a shell which consists of separate turns 

 or volutions connected by a spiral line. In this work it is used 

 for the separate and several volutions themselves. 



Since. Fine concave or raised lines. 



Stnate. Furnished with strise or fine lines. 



Sub. In composition means inclining to, but not quite d' 

 stinctly marked : as subopake means almost opake ; subcylm- 

 drical, somewhat or nearly cylindrical. 



Subulate. Tapering to a very fine point, like an awl. 



Summits. The points above the hinges in bivalve shells : the 

 beaks. 



Synonym, Synonymous. Names applied by different authors 

 to the same thing : as the Cardium rub rum of Montagu is a 

 synonym or synonymous with our Tellina rubra. 



Testaceous. Consisting of shelly matter : composed of the 

 materials which form shells. 



Transverse. Marks which run across the shell, or from one 

 side to the other; in opposition to longitudinal ones. 



Truncate. Appearing as if abruptly cut off. 



Tulercled. Covered with small wart -like knobs or protu- 

 berances. 



Tubular. Perforated all through, and open at both ends. 



Tumid. Swelling or bulging out 



Umbilicate. Furnished with a hollow indentation or perfo- 

 ration. 



Undulate. Proceeding in an irregular or wave- like line. 



Uiivalve. Consisting of a single valve or piece. 



halves. The several compartments or pieces of which the 

 whole shell is composed. 



Solutions. The distinct turns of a spire, each of which is 

 defined by the line of beparation or junction. 

 The same as volution, 



