YE 



[455 ] 



YES 



column of the Ichthyosaurus con- 

 sisted of more than one hundred 

 joints. The cervical vertebrae alone 

 of the Plesiosaurus were about 

 thirty-three in number. In birds 

 the number varies from nine to 

 twenty- three, and in living reptiles 

 from three to eight. In the Moso- 

 saurus, the whole number of verte- 

 brae amounted to one hundred and 

 thirty- three. 



YEETEBEA'TA. The whole animal 

 kingdom has been distributed into 

 four great divisions, namely, Yer- 

 tebrata, Mollusca, Articulata, and 

 Radiata. The vertebrate section 

 of the animal kingdom contains 

 five great classes, all agreeing in 

 these seven particular points: first, 

 in the possession of a brain and a 

 spinal chord, and these enclosed in 

 a skull and vertebral column ; se- 

 condly, in the possession of an in- 

 ternal bony skeleton; thirdly, in 

 the number of their limbs not ex- 

 ceeding four; fourthly, in the 

 possession of organs serving the 

 purposes of hearing, seeing, smell- 

 ing, and tasting; fifthly, in having 

 a mouth with two jaws, placed one 

 above the other, and not on oppo- 

 site sides; sixthly, in having a 

 muscular heart, and circulating red 

 blood ; seventhly, in the individual 

 distinctiveness of the sexes. In 

 the ascending series, the first of 

 the true vertebrated animals is the 

 class of Fishes ; then follows Am- 

 phibia, comprehending the various 

 forms of frogs, toads, and tritons; 

 the third class is the Reptiles. These 

 three classes are all cold-blooded. 

 The fourth class comprises the 

 birds ; these form the first class in 

 the ascending series of hot-blooded 

 animals; the fifth, or highest class, 

 comprehends Mammalia, and in- 

 cludes man. 



VE'ETEBRATED. } (vertebratus, Lat.) 



VE'RTEBEATE. ) Possessing an osse- 

 ous spinal column. 



YE'ETEX. (vertex, Lat.) The crown, 



or top of the head; the summit. 

 In conchology, in some shells the 

 most prominent part, in others the 

 apex. 



VE'ETICIL. (vertillum, Lat. a whirl.) 

 In botany, a little whorl; thus 

 when, instead of two opposite 

 leaves, three or more are produced 

 from points forming a ring on the 

 stem, such ring is termed a verticil. 



VEETICI'LLATE. ] (verticillatus, Lat.) 



YEETICI'LLATED. j "Whorled; grow- 

 ing in rings or whorls. Leaves 

 produced from three or more points, 

 forming a ring on the stem, are 

 called verticillate leaves. Yerti- 

 cillate leaves are considered as 

 being produced by the non-deve- 

 lopement of several adjacent inter- 

 nodia. 



YE'SICLE. (vesicula, a little bladder, 

 Lat.) 



1. A small bladder filled with serum. 



2. A small membranous cavity, 

 either in animals or vegetables. 

 The simplest and apparently the 

 most elementary texture met with 

 in vegetables is formed of exceed- 

 ingly minute vesicles, the coats of 

 which consist of transparent mem- 

 branes of extreme tenuity. These 

 vesicles vary from the one- thou- 

 sandth to the thirtieth of an inch 

 in diameter. 



YESI'CULAB. Consisting of vesicles; 

 containing vesicles; full of small 

 cavities, hollows, or interstices. 



YE'STIBULE. (vestilulum, Lat.) The 

 name given to a cavity of the 

 internal ear. 



YESTJ'VIAN. (from Vesuvius.} The 

 Idocrase of Haiiy ; the Yesuvienne 

 of Brochant. Pyramidal garnet. 

 A mineral of different shades of 

 green, brown, red, and sometimes, 

 though rarely, of a blue colour, 

 occurring in granular distinct con- 

 cretions, crystallized, and massive. 

 The primitive form is a four-sided 

 prism with square bases, and one 

 side of the base is to the height 

 nearly as 13 to 14; hence it differs 



