IXDEX. 



439 



Reproduction, peculiar modes of, 510 ' SAC/CIFORM, shaped like a sac or bag. 

 547; gemmiparous and fissipa- Salif'erous, or salt-bearing forma- 

 rous,5]0 515; alternate and equi- 1 tion, 650. 



vocal, 516 532 ; consequences of' Sal'pians (Gr. ffaX-rrrj, a kind offish), 

 alternate generation, 533 547. 



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

 circulation of the blood, 366 ; re- 

 spiration, 3*4. 



Rep'tiles, reign of, 658, 670 677. 



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 ; 

 in reptiles, 384 ; in insects and 

 arachnida, 385 ; in man, 386 ; in 

 birds, 388 ; lungs of man and the 

 mammalia,389,390 ; two sorts of 

 respiratory organs in articulata,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. 



Retract'ile, that may be drawn back. 



Rhi x zodonts, an order of extinct rep- 

 tiles, xxi. 672. 



Rhizo'poda ; see Foraminifera. 



Rocks, what, in a geological sense, 



646 ; their different 

 647. 



kinds, 646, 



Ro'dents (Lat rodo, I gnaw), quad- 

 rupeds with teeth for gnawing, 

 343. 



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

 1 bear), infusorial animalcules 

 characterised by the vibratile and 

 apparently rotating ciliary organs 

 upon the head. 



Rotif era, eggs of the, 546. 



Ru'minants (Lat. ru minus), quadru- 

 peds which chew the cud ; as the 

 bull and stag, 343. 



Running, 296. 



tunicated mollusks which float in 



the open sea, xxiii. 519. 

 Sau'rians (Gr. (ravpog, 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. 

 Sebaceous (Lat. sebum, tallow) 



like lard or tallow. 

 Secondary age, the reign of reotiles, 



658, 670677. 

 Secretions, the, 406 428 ; structure 



of glands, 419425 ; 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. 

 Semilu'nar, crescent-shaped, like a 



half moon. 

 Sensation, 76119. 

 Senses, the special, 120 184 

 Sep'ta (Latin), partitions. 

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

 Serrated (L&i.serra, a saw), toothed 



like a saw. 

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



base. 

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



or similar uarts. 

 Shell, 218. 



Shoulder blade, the, 270. 

 Sight, sense of 120 144. 

 Si'lex (Latin), flinty rock. 

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

 Silk-worm, metamorphoses of the, 



551. 



