INDEX 



947 



Endolymphatic sac, 854 

 Endoneurium, 827 

 Endoskeleton, 668 



development (morphogenesis) of. 668 

 Endosteum, 693 

 Endostylar cells, 885 

 Endostyle, of Petromyzon larva, 879 

 Endotheliochorial placenta, 918 

 Endotheliochorial plus syndesmochorial 



placenta, 918 

 Endothelium, 520, 748 



of blood capillaries, development of, 731 

 Enterocoel, within somite of Amphioxus 



embryo, 505 

 Entoblast, 347 {see also Hypoblast) 

 Entobronchus (Entobronchi), 647 



anterior, 646 

 Entoderm, 347 



formation of in reptiles, 361 

 Entoderm cells, mother, in opossum blas- 



tula, 365 

 Entodermal area, developmental tenden- 

 cies of during gastrulation, 412 

 of late blastula and gastrula, later deriva- 

 tives of, 533 

 tubulation of in Amphioxus, 500 

 Enveloping membranes, types of, 901 

 Environmental conditions, necessary for 



development, 901 

 Environmental factors, external, and testis 

 function, 43 

 of sexual cycles, in field mouse, 47 

 Enzyme, starch-splitting, 617 

 Epaxial (epiaxial) region, of vertebrate 



body, 494 

 Epaxial muscle groups, 706 

 Ependymal cells, 809. 816 

 Ependymal layer, of developing neural 



tube, 817 

 Epiblast, 347, 352 



Epiblast layer, of chick blastula, 343 

 Epiboly, 395, 449 



definition of, 394, 395 



description of processes concerned with, 



395 

 during gastrulation in Amphioxus, 403 

 in amphibian gastrulation. 411 

 Epicardial rudiment, 703 ' 

 Epicardium, 703 



Epidermal area, of late blastula and gas- 

 trula, later derivatives of, 533 

 Epidermal cells, ciliated. 810 

 Epidermal tube, development of, in am- 

 phibia, 474 

 Epidermis, 556 



development of in chick. 573 

 two fundamental parts of, 559 



Epididymis, as sperm-ripening structure, 29 



as storage organ, 30 



definition of, 18 



efferent ductules of, 15, 793 

 Epigastric vein, of chick embryo, 745 

 Epigenesis, theory of, 345 

 Epiglottis, 650 



development of, 650, 650 

 Epigonal area, of genital ridge, 791 

 Epigonal support, for developing sex gland, 



803 

 Epimere, definition of, 490 

 Epimyocardial rudiment, of chick heart, 



742 

 Epimyocardium, 748. 859 

 Epinephrine, 882 {see also Adrenalin) 

 Epiphysis (Epiphyses). 822, 881 



of bone, 691 

 Epipubic midpiece, of pelvic girdle, 693 

 Epithelial bed, of hair follicle, 581 

 Epithelial matrix, of hair bulb, 581 

 Epithelial nucleus, of primitive gonad, 792 

 Epithelial sheath, of tooth, 613 

 Epitheliochorial placenta, 917 

 Epithelium, germinal, 17 

 (coelomic), 791 

 effect of X-rays on, 120 

 of ovary, 58 

 origin of germ cells from, 68 



primitive, 5 19 

 Epitrichium, 559 

 Equatorial plane, of cleavage. 283 

 Equilibrium, dynamic, 854 



static. 854 

 Equipotential state, of Driesch. 377 

 Equus cahallus (horse), egg, characteristics 

 of, 207t 



fertilization, site of. 207t 



sperm entrance into egg, place of, 207t 

 Ericulus, eutherian mammal, ovarian fer- 

 tilization in, 197 

 Erinaceus europeus {see Hedgehog) 

 Erythroblasts, 733 

 Erythrocyte(s), 726, 733 



characteristics of development of, 735 

 Esophageal glands, of esophagus, 620 

 Esophagus, histology of, 620 

 Estradiol. 85 



structural formula of, 86 

 Estrogen (s), 21, 85 {see also Hormone, 

 estrogenic; Hormone, sex, fe- 

 male) 



efi"ect of upon female mammal. 88 



efi'ects of upon vertebrates other than 

 mammals. 89 

 Estrogen formation, primary control of, 87 

 Estrone, 85 



structural formula of, 86 



