960 



INDEX 



Medullary field, a gonadal sex field, 889 

 Medullary sheath of nerve fiber, 819 

 Megakaryocytes, 726 

 Megathura crenulata, secretions producing 



lysis in, 229 

 Meibomian glands, 853 

 Meiocyte, definition of, 124, 125 



female, dependent nature of maturation 

 divisions in, 144 

 Meiosis, 124 



and nuclear growth, 142, 143 

 crossing-over phenomena associated with, 



134 

 general description of, 130 

 in amphibian egg, 138 

 nuclear changes during, 128 

 peculiarities of nuclear behavior in oo- 

 cyte during, 141 

 Meitoic division, 128, 132 

 disjunctional, 133 

 equational, 133 



in spermatocyte and oocyte, 144 

 reductional, 133 

 Meiotic mitosis, 130 

 Meiotic phenomena, resume of, 145 

 Meissner, corpuscles of, 840, 842 

 Melanin, 577, 592 



granules of, in skin of mammals, 579 

 Melanophores, 591, 592 

 Membrana chalazifera, of bird's egg, 905 

 Membrana granulosa, of mature Graafian 



follicle, 71, 74 

 Membrane, embryonic, {see Embryonic 

 membrane) 

 extra-embryonic, 908 

 post-nuclear, 152 



vibratile, description of in sperm tail, 153 

 Membrane formation, and activation of 



egg, 218 

 Membranous labyrinth, of inner ear, 851, 



853 

 Menstruation, definition of, 93 



possible factors effecting, 93, 107 

 Meridional cleavage furrows, in chick 



blastoderm, 315 

 Meridional plane, of cleavage, 283 

 Meroblastic cleavage, 288 

 Merogony, 265 

 Mesencephalon, 812, 822 

 Mesenchyme, 520, 522, 656 



embryonic, contribution of to adult 

 skeletal tissue, 655 

 derivatives of, 532 

 primitive skeletogenous, 526 

 Mesenchymal packing tissue, of early em- 

 bryo, importance of, 656 

 Mesentery, dorsal, 859 

 ventral, 859 



Mesoblast, 347 



Mesobronchus of chick lung, 646 

 Mesocardium, dorsal, 748, 750, 859 

 lateral, 728. 748, 859, 863 

 formation of, 863 



role of in initial division of embry- 

 onic coelom, 860 

 ventral, 748, 859 

 Mesoderm, extension (migration) of in the 

 urodele, Pleurodeles, 417 

 introduction of word, 347 

 of head region, origin of, 522 

 of tail, origin of, 525 

 position of in embryo of Amphioxus, 

 494 

 in vertebrate embryo, 494 

 pre-chordal plate, definition of, 523 

 precocious, elaborated in human embryo, 



436 

 tubulation of, in Amphioxus, 503 

 Mesodermal areas, of late blastula and 

 gastrula, later derivatives of, 534 

 Mesodermal bands, in Amphioxus post 



gastrula, 505 

 Mesodermal cells, types of, 522 

 Mesodermal grooves, in Amphioxus post 



gastrula, 505 

 Mesogastrium, 859 

 Mesomere, definition of, 492 

 Mesorchium, 793, 803 

 Mesosalpinx, 803 

 Mesosternum, 687 

 Mesothelium, 522, 530 

 Mesovarium, 58, 803 

 Metabolic change, at fertilization, 243 

 Mesonephric kidney (Mesonephros), de- 

 velopment of 773, 778, 780, 781, 

 782 

 Mesonephric (Wolffian), duct, 771. 778, 

 787 

 origin of in Squcdus, 775 

 Metamerism, 534 



basic metamerism, 534 

 of spinal nerves, 817 

 Metamorphosis, of sperm, 17 



role of thyroid and pituitary glands in, 

 883 

 Metanephric diverticulum, origin of in 



chick, 784 

 Metanephric duct, 784, 787 

 Metanephric kidney, development of, 782, 

 784, 785 

 retroperitoneal position of, 784 

 Metanephric renal units, formation of in 



chick embryo, 784 

 Metanephrogenous tissue, 786 

 Metanephros, 773 

 Metatheria, xx 



