: ZONITES. 115 
having a hollow pit in the hinge for the cartilage. Fig. 185, V. 
lingulata. 
WHORL. A complete turn or revolution round the imaginary 
axis of a spiral shell. 
XYLOPHAGA. Sow. (évdov, zulon, wood; gaya, phago, to eat.) 
Fam. Tubicole, Lam. Descr. Equivalve, globose, closed at the 
back, with a large, angular hiatus in front; hinge with a small 
curved tooth, advancing from beneath the umbones in each 
valve. Obs. This shell, which is found in a cylindrical cavity, 
eaten in wood by the animal, resembles Teredo, but has not the 
shelly tube, nor the posterior hiatus. X. dorsalis, fig. 50, 51. 
XYLOTRYA. Leach. XyLopHaca, Sow. 
ZONITES. Montf. A genus formed of Hetix Algira, and other 
similar species with depressed spires and large umbilici; included 
in the sub-genus Helicella. Fig. 279. 
THE END. 
