972 



Reproductive duct, as a protective embry- 

 onic structure, 914 

 development of, 798, 799, 801, 802 

 Reproductive organs, changes in during re- 

 productive cycle, in bitch, 102 

 female, of the cat, 65 



of the rat, 66 

 of the human female, 59 

 Reproductive state, in relation to reproduc- 

 tive cycle, 92 

 Reproductive structures, accessory, male 

 sex hormone and development of 

 in male, 29 

 of female, 61 

 of male, 17 

 female, of the frog, 66 

 of the opossum, 64 

 of the urodele, Necturus maculosus, 

 63 

 Reproductive system, 768-804 

 development of, 788 



female, dependency on general body con- 

 ditions, 65 

 of the common flounder, Limanda 



ferruginea, 58 

 of the opossum, 63, 196 

 functions of, 769 

 male, 4 



anatomical features of, 5 

 of the vertebrate female, 57 

 Reptile, blastoderm, embryonic shield of, 

 360 

 sagittal section showing notochordal 

 inpushing (notochordal canal or 

 pouch), 419 

 claws of, 570 

 coelomic changes in, 867 

 copulatory organ of, 191 

 dermal bones in, 570 

 egg passage through oviduct in, 907 

 entoderm formation in, 361 

 heart of, 753 



independent pericardial wall develop- 

 ment in, 871 

 skin of, characteristics of, 568 

 tubulation of epidermal area in, 476 

 Reptilia, xviii 



Respiration, buccopharyngeal, 651 

 external, 635 

 internal, 635 

 Respiratory areas, of chick's lung, 647 

 Respiratory bronchioles, 650 

 Respiratory surfaces, structural relation- 

 ships of, 636 

 Respiratory system, cellular composition 



of, 650 

 Rete blastema, 795 

 Rete ovarii, rudiment of, 795 



Rete primordium, 793 



Rete-testis canals, 794 



Rete tubules, 793 



Reticular theory (doctrine) of nervous 



structure, 807 

 Reticular tissue, 657, 663 

 Reticulum, of cow's stomach, 623 

 Retina, 845 



central artery of, 846 

 Retinal rudiment, of eye, 845 

 Retzius, G., 140 



Rhahdites aberrans, and gynogenesis, 262 

 Rhabdites pellio, and gynogenesis, 262 

 Rhineodon typiis, whale shark, xvi 

 Rhinoderma darwinii, vocal brood pouch 



in male, 911, 916 

 Rhombencephalon, 812, 822 

 Rhomboidal sinus, 471 

 Ribonuclease, and egg activation, 219 

 Ribs, 686 



dorsal, 686 



ventral or pleural, 686 

 Ridge, of presumptive neural plate ma- 

 terial, 439 

 Robson, J. M., 12 

 Rock, J., 920 



Rocket sperm, of certain decapod Crus- 

 tacea, 232 

 Rodentia, xx 



Romanoff, A. J., 905, 906, 907 

 Roof plate, dorsal, 820 



ventral, 820 

 Rooster, Callus (domesticus) gallus, testis 

 in relation to reproductive ducts, 

 19 

 Root, of hair, 582 



of tooth, 605 

 Root sheath, external, of hair root, 583 



internal, structure of, 583 

 Rotation, of vertebrate embryo body, 511 

 Round ligament, 803 

 Roux, Wilhelm, 246 



hypothesis of, 215 

 Rowlands, I. W., 229 

 Rugh, R., 23, 201, 297 

 Rumen, of cow's stomach, 623 

 Rumph, P., 885 

 Runnstrom, J., 229 



theory of fertilization, 271 



Sacculus, 851, 854 



Sachs' rules of cleavage, 286 



Sacral (lumbar) enlargement, of spinal 



cord, 821 

 Sacrum, formation of, 690 

 Sainmont, G., 796 



