439 



Reproduction, peculiar modes of, 510 

 547 ; gemmiparous and fissipa- , 

 rous, 5 1 5 1 5 ; alternate and equi- 1 

 vocal, 516 532; consequences of 

 alternate generation, 533 547. 



Rep'tiles or Reptil'ia, jaws of, 340 ; 

 circulation of the blood, 366 ; re- j 

 spiration, 384. 



Rep'tiles, reign of, 658, 670677. 



Reptil'ia (Lat.repto, I creep), orRep'- 

 tiles ; the third class of vertebrate 

 animals with imperfect respiration 

 and cold blood, xxi. 



Respiration, 376 405 ; in the echi- 

 nodermata, 378, 405 ; in mollusca, 

 380, 405 ; in Crustacea, 381, 405 ; 

 in annelida, 382 ; in fishes, 383 ; 

 iu reptiles, 384 ; in insects and 

 arachnida, 385 ; in man, 3S6 ; in 

 birds, 388 ; lungs of man and the 

 mammalia, 389, 390 ; two sorts of 

 respiratory organs inarticulata,405 



Rest, the distinctive character of in- 

 organic bodies, 32. 



Re'te muco v sum, the cellular layer 

 between the scarf-skin and true 

 skin, which is the seat of the pe- 

 culiar colour of the skin, 413. 



Ret'ina (Latin), the seatof vision, 125. 



Retracr'ile, that may be drawn back. 



Rhi v zodonts, an order of extinct rep- 

 tiles, xxi. 672. 



Rhizo'poda ; see Foraminifera. 



Rocks, what, in a geological sense, 

 646 ; their different kinds, 646, 

 647. 



RoMents (Lat rodo, I gnaw), quad- 

 rupeds with teeth for gnawing, 

 343. 



Rotif' era (Lat. rota, a wheel ; fcro, 

 I bear), infusorial animalcules 

 characterised by the vibratile ;ind 

 apparently rotating ciliary organs 

 upon the head. 



Rotif era, eggs of the, 546. 



Ru'minants (Lat. ruminus), quadru- 

 peds which chew the cud , as the 

 bull and stag, 343. 



Running, 296. 



SAC'CIFORM, shaped like a sac or bag. 



Salif'erous, or salt-bearing forma- 

 tion, 650. 



Sal'pians (Gr. aaX-Trrj, a kind offish), 

 tunicated mollusks which float in 

 the open sea, xxiii. 519. 



Sau'rians (Gr. aavpoQ, a lizard), a 

 class of reptiles, including the ex- 

 isting crocodiles, and many spe- 

 cies of large size, 673. 



Scan'sores (Lat. scando, I climb), 

 birds adapted for climbing, xxi. 



Scap'ula, the, or shoulder blade. 270. 



Scap'ular arch, the, 269. 



Sclerot'ic, the principal coat of the 

 eye, 123. 



Seba x ceous (Lat. sebum, tallow) 

 like lard or tallow. 



Secondary age, the reign of reutiles, 

 658, 670677. 



Secretions, the, 406 428 ; structure 

 of glands, 419 425 ; elementary 

 parts, 426 ; origin of glands, 427 ; 

 distribution of their vessels, 428. 



Sediment'ary or stratified rocks, 646; 

 alone contain fossils, 649. 



Seg'ment, portion of a circle or 

 sphere. 



Segmentation, the act of dividing 

 into segments. 



SernuVnar, crescent-shaped, like a 

 half moon. 



Sensation, 76 119. 



Senses, the special, 120 184 



Sep'ta (Latin), partitions. 



Se'rous, (Lat. serum), watery. 



Serrat'ed (L&i.serra, a saw), toothed 

 like a saw. 



Ses'sile (Lat. sessilis], attached by a 

 base. 



Se'tae (Lat. seta, a bristle), bristles 

 or similar uarts. 



Shell, 218. 



Shoulder blade, the, 270. 



Sight, sense of 120144. 



Si'lex (Latin), flinty rock. 



Sili'ceous (Lat. silex, flint), flinty. 



Silk-worm, metamorphoses of the, 

 551. 



