470 
Primordial cranium, development of, 
428 
Primordial follicle, 27 
Proamnion, 86, 138 
Procoracoid, 435 
Proectodzeum, 170, 314, 319 
Pronephros, 190-195 
Pronucleus male and female, 34, 36 
Prosencephalon, LOS, 149 
Proventriculus, 313 
Pubis, 488, 489 
Pulmo-enteric 
mato-) 
Pulmonary arteries, 359 
Pupil of eye, 166, 272 
recesses (see pneu- 
Radius, 436 
Ramus communieans, 254, 257, 259 
Reeapitulation theory, 3; diagram 
of, 5 
Recessus hepatico-entericus, 343; re- 
eessus mesenterico-entericus, 343; 
recessus opticus, 155;  recessus 
pleuro-peritoneales, 340; recessus 
pulmo-hepatici, 340; recessus  su- 
perior sacci omenti, 340 
Rectum, 317 
Renal corpuscles, 378, 385 
Renal portal circulation, 369, 372, 
375 
Renal veins, 372 
Reproduction, development of or- 
gans of, 390-405 
Respiratory tract, 178, 325 
Rete testis, 398 
Retina, 274, 275 
Retinal zone of optic cup, 271 
Rhombencephalon, 108, 155 
Ribs, development of, 424, 425 
s (abbreviation for somites), 67 
Sacrum, 424 
Sacculus, 2938, 294 
Sacecus endolymphaticus, 169, 
290 
Saceus infundibuli, 249 
Seapula, 434, 455 
Sclerotic cout of eye, 279 
Sclerotomes, and vertebral segmenta- 
tion, 412; components of, 412; oc- 
cipital, 428; origin of, 185, 186 
Seessell’s pocket, 174 
Segmental arteries, 122, 199, 362 
Segmentation cavity, 43, 47, 55 (see 
also subgerminal cavity) 
Semeniferous tubules, 398 
Semicireular canals, 291 
Semi-lunar valves, 352 
Sensory areas of auditory labyrinth, 
origin of, 296 
289, 
‘ 
INDEX 
Septa of heart, completion of, 355, 
300; 350 
Septal gland of nose, 287 
Septum aortico-pulmonale, 351, 352; 
of auricular canal, 355; bulbo- 
auricular, 353; cushion, 351, 355; 
interauricular, 351, 354; interven- 
tricular, 351, 358, 354; of sinus 
venosus, 358 
Septum transversum, 208, 209, 334; 
derivatives of, 339; lateral closing 
folds of, 334, 337; median mass of, 
Soo 
Septum trunci et bulbi arteriosi, 351 
Sero-amniotic connection, 138, 143, 
Bld 
Sexual cords, 393, 394;. of ovary, 398; 
of testis, 395 
Sexual differentiation, 394, 395 
Sheath cells, 255 
Shell, structure of, 17 
Shell membrane, 18 
Sickle (of Koller), 71 
Sinu-auricular aperture, 357, 358 
Sinu-auricular valves, 358 
Sinus terminalis 86 (see also vena 
terminalis) 
Sinus venosus, 197, 200, 201, 357; 
horns of, 358; relation to septum 
transversum, 559 
Skeleton, general statement 
cerning origin, 407 
Skull, echondrification of, 429-4382: de- 
velopment of, 427; ossification of, 
432, 433, 434 
Somatopleure, 62, 115 
Somite, first, position in embryo, [11 
Somites, of the head, 1t4; meso- 
blastic, origin of, 110, 111; meso- 
blastic, metameric value of, 1LS4; 
primary structure of, 114 
Spermatid, 13 
Spermatocyte, 15 
Spermatogenesis, 12 
Spermatogonia, 15 
Spermatozoa, period of life 
oviduet, 385 
Spermatozoon, 9 
Spina iliaca, 440 
Spinal accessory nerve, 269 
Spinal cord, development of, 239 
Spinal nerves, components of, 254; 
development of, 252, 255; somatic 
components of, 254; splanchnic 
components of, 256 
Splanchnocranium, 427 
Splanchnopleure, 62, 115 
Spleen, 345-347 
Spongy layer of shell, 17 
Stapes, 500 
con- 
within 
