586 EMBRYOLOGY OF THE LOWER VERTEBRATES 



Fowl {continued) — 



segmentation, 516, 517 

 Fronto-nasal process, 147, 565 



Gamete, 1 



Ganoids, actinopterygian (Acipenser, Amia, 

 Lepido'steus) — 



cement-organs, 180 



gastrulation, 47 



opisthonephros, 259 



ovary, 277 



pancreas, 189 



practical hints, 563 



pronephros, 234 



segmentation, 23, 24 

 Ganoine, 326, 336 

 Gastraea, 506 

 Gastrula, 30 

 Gastrulation, 30 

 Gecko — 



endolymphatic duct, 132 



gastrulation, 48, 50 

 Genital fold, 268 



pores, 246 



ridge, 267 

 Geotria — 



pineal eyes, 100 

 Germ cavity, 16 



layer theory, Historical note, 505 



layers, delimitation, 150, 181 



wall, 17 

 Germinal epithelium, 268 

 Gills- 

 evolutionary history, 160, 449 



external, 154, 155, 157, 450 

 as forerunners of limbs, 449 



internal, 159 

 Glomerulus, 223 

 Glottis, 161 

 Gonad, 266 

 Gonocytes, 266 

 Grafted limb of Toad, 115 

 Gymnarchus — 



egg, 20 



external form, 432 



gill-filaments, 160 

 Gymnophiona — 



external gills, 155, 156 



gastrulation, 42, 43 



pronephros, 223 



segmentation, 28 



Habenular commissure, 89 



ganglia, 89- 

 Haemal arches, 292, 296 



process, 297 



spine, 297 

 Haploid, 17 

 Hatching, 459 

 Head fold, 521 



general morphology, 498 



process, 53, 521 



segmentation of, 208, 501 

 Heart, general morphology, 370, '391 



Hemispheres, cerebral, 86, 91, 95 



Hippocampus, 91 



Holoblastic, 7 



Holonephros ( = archinephros). 221 



Hyla— 



external gills, 156 



with eggs, 462 

 Hyostylic skull, 320 

 Hypobranchial, hypoglossal, muscles, 212, 



213 

 Hypochord, 290 

 Hypogeophis — 



chromophile organs, 284 



external form, 437 

 gills, 155 



gastrulation, 42, 43 



interrenals, 284 



opisthonephros, 246 



pharyngeal clefts, 159 



pronephros, 224-227 



thymus, 177 

 Hypophysis cerebri, 142 



Ichthyophis — 



intestine in section, 186 



modelling of intestine, 183 



segmentation, 28 

 Iguana, pineal eye, 97 

 Infundibular gland, 90 

 Infundibulum, 86 . 

 Intermediate cell-mass, 253 

 Interrenal, 283 



Intestine, 145, 183, 184, 185, 186 

 Invagination, 32 

 Iris, 136' 

 Isolecithal, 4 



Jacobson's organ, 128 



Kidneys, evolutionary origin, 217, 221 



Labial cartilages, 307 

 Lacerta — 



archenteron, 51 



heart, 380 



neural arches, 296 



pancreas, 191 



pineal eye, 97, 98, 99 



tympanic cavity, 343 



venous system, 422, 424 



yolk-plug, 50 

 Lachrymal groove, 551 

 Lagena, 129 

 Lamina terminalis, 90 

 Larvae, evolutionary significance, 492 

 Lateral line organs, 132 

 Latitudinal, 6 

 Lens, 133, 138, 139 

 Lepidosiren — 



brain, 85, 86, 87, 88 



buccal cavity, 149 



cement-organs, 78, 79 



chondrification of uotochordal sheath, 

 293 



chondrocranium, 308, 309, 311 



