424 



IKDEX. 



external jointed skeletons or jointed 

 limbs ; as the leech, the spider, the 

 gnat, xxii. 



Articula'ta, or Artic'ulates, 70 ; ner- 

 vous system, 115; jaws, 337; of 

 the trias period, 665, 670. 



Ascid'ian (Gr. dvKoc, a bottle), shell- 

 less acephalous mollusks, shaped 

 like a leathern bottle. 



Assimilation, the change of blood 

 into bone, muscle, &c. 401. 



Asteria v dae (Gr. darpov, a star), 

 the family of star-fishes, xxiii. 



Astre'idae, a family of polyps, found 

 in the Coral-rag, 674. 



Au'ditory (Lat. audio, I hear), per- 

 taining to the sense of hearing. 



Au'ricle(Lat.GMrz'cz/Jfl),a cavity of the 

 heart, shaped like a little ear,36 1 . 



Australia, fauna of, 615. 



Autoch'thonoi (Greek), Aborigines, 

 or first inhabitants, theory of, ap- 

 plied to the distribution of ani- 

 mals, 631. 



Automatic (Gr. avTo^aro^, self- 

 moving), a movement in a living 

 body without the intervention or 

 excitement of the will. 



Aves (Latin), birds ; the second class 

 of vertebrate animals, xxi. 



Axil'la (Lat. arm-pit), applied to 

 other parts of the animal body 

 which form a similar angle. 



Ax'olotl, a genus of reptiles, 626. 



Az'ygos (Gr. a, without ; vyo, 

 yoke), single, without fellow. 



BAC'ULITE (Lat. baculus, a staff), an 

 extinct genus of mollusks, allied 

 to the nautilus, which inhabited a 

 straight-chambered shell, resem- 

 bling a staff. 



Bal'anoids (Gr. fiaXai'og, an acorn), 

 a family of sessile cirripeds, the 

 shells of which are commonly 

 called acorn shells. 



Bar'nacle ; see Anatifa. 



Bas'ilar (Lat. basis, a base), belong- 

 ing to the base of the skull. 



Bas'ilosaurus, an extinct cetacean, 

 680. 



Batra'chians (Gr. fla-pa-%oQ, a frog), 

 the order of reptiles including the 

 frog, xxi. 



Batra x chians, peculiar species of, 626. 



Belem'nite (Gr. j3k\tp,vo^, a dart), 

 an extinct genus of mollusks ; 

 animals allied to the sepia, and 

 provided with a long, straight, 

 cbambered conical shell in the in- 

 terior of the body, 673. 



Bi, or Bis, a Latin prefix, signifying 

 "twice, " as in the following words : 



BPfid, cleft into two parts, or forked. 



Bifurcate, divided into two prongs 

 or forks. 



BiMateral, having two symmetrical 

 sides. 



Bi'lobed, divided into two lobes. 



Bipartite, divided into two parts. 



Bi v peds (Lat. bis, two, pes, a foot), 

 animals with two feet, as man and 

 birds. 



Bird tracks, fossil, 670. 



Birds, the second division of the ani- 

 mal kingdom, xxi. 



Birds, muscular system of, 227 ; 

 stomach of, 330. 



Bis (Latin), two, or twice; used in 

 composition only. 



Bi y valve, a shell of two parts, closing 

 like a double door, 662. 



Blas'toderm, the embryonic germ. 



Blood, the, and circulation, 350 375. 



Blood, the, its constituents, '^50 

 351 ; corpuscles, 352; colour, 

 353 ; its presence an essential 

 condition of life, 354; circulation, 

 .361 375; changes that it under- 

 goes in circulation, 395. 



Bone, analysis of, 238 ; basis, 239 ; 

 microscopic structure, 240 ; the 

 various bones of the human ske- 

 leton, 235, 241278. 



Bot'ryoi'dal (Gr. fiorpvs, a bunch of 

 grapes), having the form of a 

 bunch of grapes. 



Bould'ers, 684. 



