USED IN NATURAL HISTORY. 



153 



UH'SXJS. Lat. A bear. 



U'RUS. Lat. A buffalo. 



USITATI'SSIMUM. Lat. Most com- 

 mon; familiar. 



USTULA'TION. The roasting of ores, 

 to volatilize the sulphur, or any 

 of their volatile ingredients. 



UTRI'CULA fr. lat. utriculus, a little 

 bottle. Utricle. A little bladder 

 or sac in the structure or tissue of 

 plants, (figs. 2, 3, p. 11, Book vii). 



UTRI'CULE. Lat. plur. of utricula. 



U'TRICLE. In botany, a caryopsis 

 which does not adhere to the 

 seed. 



UTRI'CULAR. Of or relating to utri- 

 cula or vesicles. 



VA'CUUM. fr. lat. vacuus, empty. A 

 portion of space void of matter. 



VAGI'NA. Lat. A sheath. In bo- 

 tany, a leafy expansion surround- 

 ing the stem in some plants. 



VAGIXA'LIS. fr. lat. vagina, a sheath. 

 A genus of birds. 



VA'GIN ATE. Applied to a leaf when 

 it embraces or sheathes the stem. 

 Also, to those polyps which are 

 enclosed in a calcareous sheath 

 or tube. 



VAGI'NULA. 7 Lat. A little sheath 



VAGI'NULUS. 3 or scabbard. A ge- 

 nus of naked gasteropods. 



VALESXE'RIA. Generic name of an 

 aquatic plant,channel weed, upon 

 which the canvass -back ducks 

 feed, and to which the peculiar 

 and delicious flavour of their 

 flesh, is said to be attributable. 

 The specific name of the canvass- 

 back duck. 



VALLEY. A space lying between 

 opposite ridges of mountains or 

 hills. 



VALLEYS OF DISLOCATION. (See p. 

 163-4, Book viii). 



VALLEYS OF ELEVATION. Closed 



valleys, (p. 161, Book viii). 



VALVA'TA. A genus of fresh-water 

 snails, (fig. 48, p. 48, Book v). 



VALVE. fr. lat. valvce, folding-doors, 

 small door. Any membrane or 

 7* 



doubling of membrane which pre- 

 vents fluids from flowing back in 

 the vessels and canals of the ani- 

 mal bod^fc In botany, valves are 

 the parts of the seed-vessel, into 

 which it finally separates; also, 

 the leaves which make up a 

 glume, or spatha. In conchology, 

 the pieces which constitute the 

 covering of acephalous mollusks 

 or bivalves. 



VALVED. ? In botany, consisting 



VAL'VULAR. of valves or seed- 

 cells. 



VANE'LLUS. Generic name of the 

 lapwing. 



VANES'SA fr. gr. phanes, one of the 

 names of Venus. A genus of 

 butterflies. 



VAPORIZA'TION-. The conversion of 

 a liquid or of a solid body into 

 vapour by the application of heat. 



VA'POUR. A light, expansible, and 

 generally invisible gas, which in 

 its mechanical properties, while 

 it exists, resembles air, but is sub- 

 ject to be condensed into the li- 

 quid or solid form by reduction 

 of its temperature. 



VA'RIANS. Lat. Varying, chang- 

 ing. 



VA'RicosE.-Swollen here and there. 



VARI'ETIES. Individuals subordi- 

 nate to species. The variety dif- 

 fers from the species in points of 

 structure which are developed 

 only under particular circum- 

 stances, and which are not essen- 

 tial to the species. The characters 

 on which a species is founded 

 should be invariable under all 

 circumstances. 



VA'RICES. fr. lat. varix, a swollen, 

 vein. Longitudinal ribs in uni- 

 valve shells. 



VAS'CULAR. fr. lat. vasculum, a little 

 vessel. Having numerous ves 

 sels. Vascular plants is a term 

 applied to the two great divisions 

 of plants called Exogens and n- 

 dogens t owing to the high devel- 

 opement of vascular tissue in them, 



