INDEX 



963 



Nail fold (groove), of developing finger 



nail, 584 

 Nail matrix, 584 

 Nail plate (Unguis), 584, 585 



ventral (subunguis), 585 

 Nails, development of, 584 



diagrams of, 583 

 Nasal processes, 844 



median, 844 

 Nasal septum, 844 

 Naso-lacrimal duct, 853 

 Naso-lacrimal groove, 853 

 Natatorial adaptations, of muscles, 706 

 Natrix sipedon, xix 

 Neal, H. V., 716 

 Nebenkern, mitochondrial, 151 



or mitochondrial body, 152 

 Neck, of sperm, 149 



of tooth, 605 

 Nectophrynoides vivipara, xviii, 189 

 Necturus, development of vertebrae in, 

 685 



differentiation of myotomes in, 714 



muscles of, 707 



skin of, 566 



spermatheca of, 190 

 Necturus maculosus (Mud puppy), xvii 



branchial-pouch-groove perforation of, 

 640 



characteristics of egg, site of fertiliza- 

 tion, and place of sperm entrance 

 into egg, 204t 



cleavage of egg in, 307, 308 



development of gills in, 641 



development of skin in, 567 



egg, size of, 307 



external gills of early stages, 639, 640 



first cleavage plane of dgg in, 287 



lung of, 644 



skeletal muscle development in, 708 



stages of normal development of, 473 



yolk sac of, 908 

 Nelsen, O. E., 796 

 Neoceratodus forsteri, lungfish, xvi 

 Neornithes, xix 

 Nephric, use of term, 772 

 Nephric (Renal) units (Nephrons), 772 



development of in mammalian kidney, 

 786 



formation of in mammal (human), 784 

 Nephrocoel, of frog pronephric kidney, 776 

 Nephrogenic cord, 781, 782, 786 

 Nephrons (Nephric units), 772 



types of, in developing vertebrate em- 

 bryos, 773 

 Nephros, 772 

 Nephrostomes, 780 



Nephrotomes, or segments of nephrotomic 



plate, 773, 774 

 Nephrotomic mesoderm (urogenital meso- 

 derm), synonymous with meso- 

 mere, 492 

 Nephrotomic plate, 772, 786 

 Nereis, fertilization in, 239, 241, 260 



sperrn entrance into egg of, 212 

 Nerve(s), abducens (cranial n. VI), 829 

 acoustic (cranial n. VIII), 830 

 chorda tympani, 829, 843 

 cranial, abducens, (cranial n. VI), 829 

 facial (cranial n. VII), 829 

 functional components of, 824 

 glossopharyngeal (cranial n. IX), 718, 



830 

 hypoglossal (cranial n. XII), 717, 833 

 nervus terminalis (cranial n. O), 827 

 nuclei of origin and termination of 



cranial nerves, 824 

 oculomotor (cranial n. HI). 827 

 olfactory (cranial n. I), 827 

 optic (cranial n. II), 827 

 origin, development, and function of, 



827 

 spinal accessory (cranial n. XI), 718, 



833 

 trigeminal (cranial n. V), 717, 828 

 trochlear (cranial n. IV), 828 

 vagus (cranial n. X), 831 

 Nerve fibers, termination of, 838 

 Nerve-net theory (doctrine), of nervous 



structure, 807 

 Nervous layer, of primitive epidermis of 



frog embryo, 568 

 Nervous system, 805-856 

 capsular cells of, 819 

 central. 809 

 definition of, 807 

 functional unit of, 807 

 peripheral, 809 



structural fundamentals of, 812 

 supporting tissue of, 809 

 vertebrate, structural divisions of, 809 

 Nervous tissues, embryonic origin of, 810 



histogenesis of, 814 

 Neural ectoderm, solid keel of, in teleost 



and bony ganoid fishes, 458 

 Neural fold method, of neuralization, 466 

 Neural (ganglionic) crest, 469, 810, 812 

 Neural groove, 466 



Neural plate, in Amphioxus gastrula, 495 

 Neural plate area, of late blastula and gas- 

 trula, later derivatives of, 533, 

 810 

 Neural tissue, 520 



