GLOSSARY. 395 



WHORL. The spiral turn of a univalve shell. 



XIPHOSURA (Gr. xiphos, a sword ; and ov.ra, tail). An order of Crustacea, 

 comprising tbe LinwUi or King-Crabs, characterised by their long sword- 

 like tails. 



XYLOBIUS (Gr. xuton, wood ; bios, life). An extinct genus of Myriapods, 

 named in allusion to the fact that the animal lived on decaying wood. 



ZAPHRENTIS (proper name). A genus of Rugose Corals. 



ZEUGLODONTID^E (Gr. zeugle, a yoke ; odons, a tooth). An extinct family of 

 Cetaceans, in which the moiar teeth are two-fauged, and look as if composed 

 of two parts united by a neck. 



ZOOPHYTE (Gr. zoon, animal ; phuton, plant). Loosely applied to many plant- 

 like animals, such as Sponges, Corals, Sea-anemones, Sea-mats, &c. 



