968 



Periderm, 558, 559, 579, 908 



of primitive epidermis of frog embryo, 

 568 

 Perilymph, of ear, 854 

 Perimysium, external, 701 



internal, 701 

 Perineurium, 827 

 Periosteal bone formation, 667 

 Periosteal tissue, 693 

 Periosteum, 666, 667, 693 

 Peripheral nervous system, development 

 of, 823 



early histogenesis of, 817 



structural divisions of, 823 

 Perissodactyla, xx 

 Peritoneal cavity, 858, 863, 873 

 Peritoneal division, of coelom, primary, 



formation of, 859 

 Peritoneal support of the ovary, 58 

 Peritoneopericardial membrane, 864, 866 

 Perivitelline fluid, 235 

 Perivitelline space, 167, 235, 903 

 Petroniyzon, ammocoetes larva of, 885 



embryo of, partial eversion of oral cav- 

 ity in, 607 



pineal body of, 881 



stomach area of, 621 

 Petroniyzon ftuviatilis, hypophysis of, 877 

 Petroniyzon marinas, sea lamprey, xvi 

 Pflijger's cords, proliferation of, 796 

 Pharyngeal area, role of in respiration, 619 

 Pharyngeal (branchial) pouches, 527, 618, 



619 

 Pharyngeal diverticula, 902 

 Pharyngeal glands, of internal secretion. 



619 

 Pharyngeal grooves, 618 

 Pharyngeal membrane, 599, 632 

 Pharyngeal (oral) evagination, of foregut, 



482 

 Pharyngeal placentae, 902 

 Pharyngeal veins, 737 

 Pharynx, 618, 718 

 Pharynx, diverticula of, 601 



functions of, 601 

 Phillips, R. W., 195 

 Phrenic nerve, origin of, 718 

 Phyrynosoma cornuturn, xviii 

 Physiological maturation, of sperm, in re- 

 productive ducts, 169 

 in testes, 169 

 Physoclistous type, of air bladder, 643 

 Physostomous type, of air bladder, 643 

 Pia mater, 821 



Pig embryo, developing coils in digestive 

 tract of, 628 



development of body form in, 498 



early development of, 298, 364, 496 



Pig embryo — (Continued) 

 gastrulation in, 433 

 implantation of, 923 

 of about 9.5 to 12 mm., 546-550 

 primitive streak, notochord, and meso- 

 dermal migration in, 434 

 sections of, 497 

 sections of embryonic (germ) disc of, 



435 

 tooth development in, 614 

 Pigeon, female, reproductive organs of, 

 192 

 maturation phenomena in egg of, 267 

 Pigment, in hair, 592 

 Pigment cells, origin of from neural crest 



ceils, 469 

 Pigmented coat, of eye, rudiment of, 845 

 Pike, walleyed, fertilization of, 232 

 Pincus, G., 12, 119, 198, 219, 305 

 Pineal body, 822, 881 

 Pinkus, F., 583, 827 

 Pinna (External ear), 851, 855 

 Pinnipedia, xx 

 Pipa pipa, xviii 

 Pipefish, brood pouch in, 188 

 Pipefishes, egg migration of to brood pouch 



of male, 199 

 Pit organs, 843 



Pituitary gland (Hypophysis cerebri), 39, 

 876 

 anterior lobe of, 876 

 efi"ect of on development of chick, 884 

 effect of on development of mammal, 



885 

 in vertebrate embryology, general con- 

 clusions, 886 

 influence of in anuran metamorphosis, 



883 

 influence of on development of fishes, 



885 

 pars intermedia of, 877 

 posterior lobe of, 877 

 role of secretions of in color change, 594 

 Pituitary gonadotrophins, effects on ovaries 

 of vertebrates other than mam- 

 mals, 73 

 Placenta, 917, 922 



as source of estrogen, 87 

 formation of, in human embryo, 921 

 functions of, 926 

 of mouse, 915 

 oral, 930 



primary, of monkey, 922 

 secondary, of monkey, 922 

 types of, 917, 918 

 Placenta fetalis, 922 

 Placenta materna, 922 

 Placental relationships, 913 



