VIT- 



347 



WAN- 



vitrella (vitrgl'a) n. [L. vitrum, glass.] 

 A crystalline cone cell of an in- 

 vertebrate eye (zool.). 



vitreodentine (vit'reodgn'tin) n. [L. 

 vitreus, glassy ; dens, tooth.] A 

 very hard variety of dentine (zool.}. 



vitreous (vit'reus) a. [L. vitreus, 

 glassy.] Transparent ; appl. a clear 

 jelly-like substance in the inner 

 chamber of the eye (anat.). 



vitta (vlt'a) ., vittae (vlt'e) plu. [L. 

 vitta, band or fillet.] One of the 

 oil receptacles in an umbellifer fruit 

 (bot.) ; a band of colour (zool.). 



viviflcation (viv'ifika'shun) n. [L. 

 vivus, living ; facere, to make.] 

 One of the series of changes in 

 assimilation by which the proteid 

 material which has been taken up 

 by the cell is able to exhibit the 

 phenomena of living protoplasm 

 (phys.). 



vlviparity (viv'ipar'itT) n. [L. vivus, 

 alive ; parere, to beget.] The con- 

 dition of bringing the young forth 

 alive (zool.) ; or of multiplying by 

 means of shoots or bulbils (bot.). 



viviparous (vivip'ariis) a. [L. vivus, 

 living ; parere, to beget.] Bringing 

 forth the young alive ; cf. oviparous 

 (zool.) ; germinating while still 

 attached to the parent (hot.). 



vocal (vo'kal) a. [L. -vox, voice.] 

 Pert, voice or utterance of sounds. 



vocal cords, folds of mucous mem- 

 brane projecting into the larynx. 



volar (vo'lar) a. [L. vola, the palm of 

 the hand.] Pert, palm of the hand 

 or to the sole of the foot (anat.). 



Volkmann's canals (folk'm&nz), 

 simple canals piercing the circum- 

 ferential or periosteal lamellae of 

 bone for the passage of blood- 

 vessels (phys.). 



voluble (vol'ubl) a. [L. volvere, to 

 twist.] Twining spirally (bot.). 



voluntary (vol'untari) a. [ L. voluntas, 

 will.] Subject to or regulated by 

 the will ; appl. action of muscles 

 (phys.}. 



volute (volut') a. [L. volvere, to 

 twist.] Spirally twisted (zool.). 



volutin grains, grains formed in 

 cytoplasm and representing a food- 

 material which is absorbed by the 

 nucleus in growth and formation of 

 chromatin (cyt.). 



volution (vSlu'shun) n. [L. volvere. 



to twist.] The spiral twists of a 



shell (zool.). 

 volva (vbl'va) n. [L. volva, wrapper.] 



The sac-like structure enveloping 



the stipes of an Agaric (bot.). 

 volvate (vol'vat) a. [L. volva> 



wrapper.] Provided with a volva 



(bot.). 



vomer (vo'mer) n. [L. vonier, plough- 

 share.] A bone in the nasal region 



of the skull (anat.). 

 vomerine (vo'mgrin) a. [L. vomer, 



ploughshare.] Pert, the vomer ; 



appl. teeth (zool.). 

 vomeronasal (vo'me'rona'zal) a. '[L. 



vomer, ploughshare ; nasus, nose.] 



Appl. cartilage and organ in region 



of vomer and nasal cavity (anat.). 

 von Baer's law, see recapitulation 



theory, 

 vortex (vof'tfiks) n. [L. vortex; 



vortex.] The spiral arrangement 



of the muscle fibres at the apex of 



the heart (anat.). 

 vulva (vul'va) . [L. vulva, vulva.) 



The external parts of the female 



genital organs (anat.). 

 vulviform (vul'vlform) a. [L. vulva, 



vulva ; forma, shape.] Like a cleft 



with projecting lips (bot.) ; shaped 



like a vulva (zool.). 

 vulvouterine (vul'vou'tgrin) a. [L 



vulva, vulva ; uterus, womb.] Pert. 



vulva and the uterus (anat.). 

 vulvovaginal (vul'vovaj'mal) a. [L 



vulva, vulva; vagina, sheath.] Per*. 



the vulva and the vagina (anat.). 



w 



Wallace's Line, an imaginary line 

 separating the Australian and 

 Oriental regions : it ran between 

 Bali and Lombok, between Celebes 

 and Borneo, and then to the east- 

 ward of the Philippines (zool.). 



Wallerian degeneration, the de- 

 generation of nerve fibres following 

 section, this proceeds from the 

 seat of the injury along the axon 

 away from the neuron (phys.). 



wandering cells, amoeboid cells of 

 mesogloea ; migratory leucocytes of 

 areolar tissue (zool.). 



