GLOSSARY. 147 



XIPHOSVRA (|P OS sword ; ovpd, tail), a synonym of Merostomata, from the long 

 sharp tail of Limulus. 



ZEUGLODON f (vy\r], a yoke-strap; oSouj, tooth), an extinct genus of Cetacea, with 

 teeth consisting of two parts united by a narrow band. 



ZONARY (&VT], zona, a belt), that form of deciduous placenta in which the foetal 

 villi are arranged in a belt. A similar though broader band in a non- 

 deciduous one is called " diffuse," or sometimes " zonular." 



Zoom ((<aov an animal; eTSos, resemblance), a term applied to the individuals of 

 compound organisms, as the polyps of a polypidom among Ccelenterata. 



ZYUAXTUUM (C U 7^"> a yoke; antrum, a cave), a hollow in the vertebrae of serpents 

 by which an additional articulation is provided with the vertebra next behind. 



ZYGAPOPHYSIS (vy6v, a yoke ; airdQva-is, an outgrowth), a name given to the arti- 

 culating processes of vertebras which correspond with those of Man. 



ZYGOMA (tfry<afi.a, fr. vy6v), the arch at the side of the skull formed by the jugal 

 or yoke-bone (os malse of human anatomy), articulating with the squamosal. 



ZYGOSPHEXE ((vy6v, e^v, wedge), a conical process on the front of the vertebrfe of 

 OphirJia which fits into the zygantrum of that next in front. 



