IN DESCRIBING SHELLS. 83 



Cauda, the tail, is found at that part of the a]jerturc which is 

 furthest fi'om the spire. 



Labia, the hps, are the edges of the aperture, the outer side of 

 which is called the lip, labi'^an* ; it is also sometimes called 

 the outer or right lip, labium exterius vel dextrum ; the inner 

 side, or that part which joins to the preceding- turn or whorl, 

 is called the inner lip, labium interius -f ; or the pillar lip, 

 labium columell(E'^ ; or the left lip, labium sinistrorsum. 



Operculum is that small piece which is separate from the shell, 

 but attached to the foot of the animal, with which it closes 

 the opening when it retires into its shell ; this piece is 

 wanting in a great many shells. 



OF THE SPIRE, SPIRA. 



Truncata is with the spire flat as if cut off, and forms the base 

 of the conic shape of Linnaeus's first division of Conus. 



Obliterata is when the spire can hardly be perceived, as in 

 Bulla Ficus and Valuta Monilis. 



Prominens is when the spire is rather prominent, as in Valuta 

 Ispidula. 



Producta is when the spire is much more prominent or pro- 

 duced, as in Murex despectus and corneus. 



lionga is when it is very long in proportion to the shell, as in 

 Strombus Pes pelecani. 



* See Valuta glabella of Linnseus's Systetna Natures, 12th edit. 

 + See Nerita Mammilla, ibid. % See genus Nerita, ibid. 



