APPENDIX III 383 



UTRicuLus (L. a little bag), the cavity of the inner ear, from which the 

 semicircular canals arise. 



VAGINA (L. a sheath), in mammalian anatomy the outer part of the 

 reproductive canal; it is homologous with the ends of the oviducts; it 

 is connected with the uterus through the cervical opening. 



VAGUS (L. wandering), the tenth cranial nerve. 



VAS (L. a duct), specifically the ducts connected with the testes; the 

 vasa efferentia form the epidid3'mis; the paired vasa deferentia con- 

 duct the sperms to the urethra. 



VEXA (L. a vein), as vena cava; venous; sinus venosus. 



VENTRICLE (L. diminutive of venter, belly) ; specifically the cavities of the 

 brain; or the muscular chambers of the heart. 



VERMIS (L. a worm), as the vermis of the cerebellum; vermiform ap- 

 pendix. 



VERTEBRA (L. a joint), the single structural units of the vertebral column. 



VILLI (L. villus, shaggy hair), the hair-like processes lining the intestine. 



VISCERA (L. viscus, an internal organ), the internal organs, including the 

 digestive tract and the glands. 



VITELLINE (L. vitellus, yolk), specifically the paired embryonic veins 

 which form the heart. 



VITREOUS (L. glassy), in vitreous humor of the eye. 



"Wolffian (from Wolff, a German anatomist, 1733-1794), the mesonephric 

 ducts of the amniotes from which develop the vasa deferentia. Also, 

 the mesonephros, or Wolffian body. 



zooN (G. animal), a combining form; spermatozoa; zoologj'; Cenozoic. 



ZYG, ZYGO (G. zygon, yoke), combined in zygomatic arch, zygote, etc. 



zygomatic arch (G. zygon), the cheek bone of the mammals and mam- 

 mal-like reptiles; homologous with the ventral margin of the skull, 

 and formed by the enlargement of the lateral fenestra of the skull. 



