948 



Estrous cycle, factors controlling, 96 



follicular phase of, 92 



in mammals, 92 



luteal phase of, 92 

 Estrus, definition of, 93 



relation of to activity of oviduct during 

 egg transport, 200 



relation of to ovulation, 95 

 Eustachian duct (see Eustachian tube) 

 Eustachian tube, 841, 851. 855 

 Eustachian valve, of chick heart, 756 

 Eutheria, xx 

 Evagination, scrotal, 1 1 

 Evans, H. M., 41 

 "Ex ovo omnia," 53, 54 

 Excretory duct, main, of kidney, 772 

 Excretory system, 768 



development of, 772 



functions of, 769 

 Exoccipital center, of ossification, 695 

 Exocrine glands, 875 

 Exogastrulation, 449 

 Exogenous sources, of food for embryo, 



902 

 Exoskeleton, 668 

 Extension, in gastrulation, definition of, 



398 

 External auditory meatus, 855 

 External naris, 844 

 Exteroceptive field, 842 

 Extodermal expansion, definition of, 395 



{see also Epiboly) 

 Extra-embryonic coelom, 909 

 Extra-embryonic membranes, 901 



diagrams of. 909 



in human embryo, 972 

 Eycleshymer, A. C, 306, 308, 473 

 Eye, accessory structures of, 853 



development of, 844 

 special aspects of, 846 



extrinsic muscles of, development of, 

 716 



general structure of, 844 

 Eyelids, 853 



Fabricius, bursa of, 602, 881 

 Falciform ligament, 866 



of liver, 873 

 Falciform process, of teleost fish eye, 849 

 Fallopian tube, in rabbit, behavior in sperm 



transport, 193 

 Fankhauser, G., 160, 270 

 Fascia deep, 556 



spermatic, external, 13 

 internal, 13 

 middle, 13 



Fascia deep — (Continued) 

 superficial, 556 

 perineal, 12 

 Fasciculus (Fasciculi), definition of, 701 



or muscle fiber bundles, 701 

 Fasciculus cuneatus, 821 

 Fasciculus gracilis, 821 

 Fat, brown, 664, 665 

 types of, 664 

 white, 664 

 Fat droplets, origin of, 157 

 Feather(s), after shaft, formation of, 571, 

 578 

 contour, 571 



development of, 575 

 early phase of, 575 

 secondary phase of, 575 

 development of, 577 



in chick, 572 

 down, 573 



later, development of, 578 

 filoplumous, development of, 578 

 general structure of, 571 

 nestling down, development of, 573 

 Feather follicle, 571 

 Feather vane, formation of, 576 

 Felis (see Cat, Felis) 



Felix, W., 778, 785, 787, 791, 792, 794, 797 

 Fenestra cochlea, 851 

 Fenestra ovalis, 851 

 Fenestra rotunda, 851 

 Fenestra vestibuli, 557 

 Fenestrae, of atrial septum of chick heart, 



754 

 Ferret, pituitary ablation of, 39 

 Ferret, Putorius vulgaris, effect of light 

 upon reproductive activities, 44, 

 45 

 Fertilization, 21 1 

 areas of, 189 



behavior of gametes during, 221 

 changes in physiological activities at, 243 

 definition, 113, 211 

 dry, 232 



external, and reproductive duct, 17 

 fusion of gametes at, 234 

 in Echidna, 254, 255 

 in Gambusia affinis, 199 

 in hen's egg, 252 

 in Heterandria formosa, 199 

 in ovary, 197 



in Styela (Cynthia) partita, 224, 245 

 internal, general features of, 189 

 reproductive duct in, 18 

 sperm transport in, 189 

 metabolic change at, 243 

 movements of ooplasmic substances dur- 

 ing Styela, 264 



