ULTRAMARINE 



335 



UNIVALENT 



Ultramarine, (ul-tra-ma-rt-n'). [L. ultra, be- 

 yond; >nar, sea.] A blue colouring mat- 

 ter : a mineral, chiefly phosphate of alumi- 

 num. Ai-tiriciul If., made from silicate of 

 aluminum, soda, sulphur, carbon, &c. Na- 

 tural tf. = Lapiz-lazuli. 



Ulva. (ul'va). [L. ulvu, sedge.] A sea-weed, 

 belonging to Algae. 



Ulvacess, (ul-va'se-e). [Ulva, q.9.] A sub- 

 division Of AlgSB. 



Umbel, (um'bel). [L. umbella, small shade.] 

 A variety of inflorescence, 

 h the flower stalks 

 all rise from one point of 

 the stem. 



Umbellate*, (um-bel-la'- 

 let). [Umbel, q.v.] Plants 

 with dichlaraydeons poly- 

 petalous flowers, forming 

 a division of Epigynous 

 Exogens. 



Umbclliferss, (um-bel-lif- 

 er-*). [Umbel, ..; L. 

 /fro, I carry. ]=Apiacese, 



TJmber, (unVbrr). [Umbria, in Italy.] 1. A 

 soft earthy com- 

 pound of per- 

 oxideof iron and 

 manganese, used 

 as a brown pig- 

 ment. 2. An 

 African crow-like 

 bird=Soopns um- 



!.! L 



Umbilical, (nm- 

 bil'i-kal). [Um- 

 bilicus, <y.r.) Re- 

 lating to the 

 n m ;. 



Umbilicus, (um-bil'i-ku*). [The Latin word.] 

 =The navel: a depression in the abdomen of 

 a mammalian animal, being the remains of 

 the point of attachment of the umbilical 

 cord, or cord connecting the parent and child 

 previous to birth. 



Umbo, (um'bo). [The Latin word.]=Beak of 

 a shell; and generally any pointed projection. 



Umbra, (um'bra). [L. umbra, shadow.] Tho 

 darker portion of a shadow. 



Umbrella. U. oird=Cephalopterus ornatns: 

 a crow-like bird of 8. America. 



Umbriel, (um'bri-el). A satellite of Uranus. 



Unaw. v. Bradypus. 



Unakalkay. (u-n.-i-kal'ka). The chief star of 

 the constellation Serpens. 



Uncaria, (un-ka'ri-a). A plant belonging to 

 Rubiacea;, from which a dye-stuff, gambier, 

 i~ obtained. 



Undecagon, ( un-dek'a-gon ). [L. undeeim, 

 eleven ; gonia, angle.] A plane figure hav- 

 ing eleven sides, and, therefore, eleven 

 angles. 



Under -clay. Beds of clay, or firestone, 

 usually found below coal, in which are 

 found roots of trees, the trunks of which, 

 usually flattened, are in the coal ; also 

 used for any fossil soil which once supported 

 trees. 



Undershot V. wheel : a wheel moved by a 



stream of water passing under it 

 Undulation, (un-dtt- 



lii'bhun). [L. un- 



dula, small wave.] 



Vibration: wave of 



motion ; alternate 



motion. >x 



of light. That light' 

 is a vibratory mo- 

 tion of the particles Uudenbot-wheeL 

 of a luminiferous ether. 



Ungual, (ung'wal). [L. unyuit, nail.] Re- 

 lating to claws, nails, or hoofs. If. bonet^s 

 lachrymal bone*: two small bones in the 

 orbit of each eye. 



Unguents, ( ung'gwenta ). [L. unyufnturn, 

 ointment.] Any soft composition used as 

 an ointment, or for the lubrication of 

 machinery. 



Unguiculata. (nng'wik-a-lu'ta). [L. unpuii. 

 nail.] Animals having nails or claws ; used 

 by Owen for Quadrumana and Cturnivora. 



Unguis, (ung'wis). [The Latin word.] Noil 

 or claw. 



UngulaU, (nn-gu-la'ta). [L. ungula, hoof.] 

 HffitfH quadrupeds: hones, 

 pigs, &c. ; a division of Mam- 

 malia, marked by a non-de- 

 ciduate placenta, enamelled 

 teeth, and hoof-like nails en- 

 closing the toes. 



Unguligrade, ( un-Ru'li-Kr.1.1). 

 [L. vnyula, hoof; gradior, 

 I walk.] = Horse, &c.: ani- 

 mals walking on the tips of their hoofed 

 digits. 



Uniauriculate animals=Gasteropoda, q.v. 



Uniaxial. (a-ni-aks'i-al). [L. vnut, one; Axis, 

 q.v.] U. cryttaU: crystals having one 

 optic axis. U. development: in all ver- 

 tebrate animals, some molluscs and annu- 

 losa; in some of exogeus, endogens, algiu, 

 and fungi. 



Unicorn, (u'ni-kawrn). [L. unicornii, one- 

 horned.] 1. Monoceros: a southern constel- 

 lation. 2. A fabulous animal, represented 

 in heraldry. Sta f/".=Narwhal, q.v. 



Unio, (u'ni-6). [The Latin name.] A fresh- 

 water lamellibranchiate animal; also called 

 Rtver-musssJfc 



Unisexual, (u-ni-seks'u-al). U. plant=T)ic- 

 linous plants; those having stamena and 

 pistils in different flowers. 



Unison, (u'ni-son). [L. unus, one; tonus, 

 sound.] Sounds caused by the same number 

 of vibrations, and therefore having the same 

 pitch, are said to be in unison. 



Unit. U. jar = A small Leyden jar, the 

 charge of which is taken as a unit of electric 

 tension. U. of capacity Cubic foot: in 

 French=Litre. Absolute U. of force=Dyne 

 =the force which acting on a gramme for one 

 second generates a velocity of a centimetre 

 per second. Absolute U. ofwork=Vfork done 

 by a dyne working for the distance of a cen- 

 timetre. 



Univalent=Monatomic. v. Monads. 



