GLOSSARY. 395 



Whorl. The spiral tiirn of a univalve shell. 



XiPHosuKA (Gr, xijohos, a sword ; and oura, tail). An order of Crustacea, 

 comprising the Limuli or King-Crabs, characterised by their long sword- 

 like tails. 



Xylobits (Gr. xulon, wood ; bios, life). An extinct genus of Myriapods, 

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



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



Zeuglodontid^ (Gr. zeugle, a yoke ; odous, a tooth). An extinct family of 

 Cetaceans, in which the molar teeth are two-fanged, 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. 



