376 INDEX-GLOSSARY. 



Gallus bankiva = Fowl, 229. 



Ganglion (ydyyXioi/, a small tumour) An aggregation of nerve-cells, 35, 



66, 81; Abdominal, 101, 102; Anal, 52; Buccal, 133; Cerebral, 35, 36, 



66, 81,100, 132; Cerebro-pleural, 119; Cervical, 303 ; Cceliac, 303 ; 



Gasserian, 212, 215, 253 ; Infra-cesophageal, 81 ; Lateral, 52 ; Mesen- 



teric, 303; Optic, 103; Parieto-splanchnic, 119; Pedal, 119, 133; 



Pleuro- visceral, 133 ; Post-oesophageal, 101 ; Semilunar, 303 ; Spinal, 



215 ; Sympathetic, 171 ; Thoracic, 101 ; Vagus, 213, 303 ; Ventral, 35, 



52 ; Visceral, 119. 

 Ganoidei, 153, 349. 

 Gastric juice, 194. 

 Gastric mill, 92. 



Gastrolith (yao-rj/p, the stomach ; \i'0os, a stone), 93. 

 Gastrula (dim. from gaster, yao-rj/p) An embryonic stage, the typical form 



of which is a two-layered sac with digestive cavity opening to the 



exterior, 38, 68, 105, 148, 260. 



Gastrulation The formation of the gastrula, 68, 148, 224. 

 Gemmation (gemma, a bud) Asexual reproduction by budding, 24. 

 Generative or Genital Organs. See Reproductive Organs. 

 Genus, 3, 4. 

 Geology, 347. 

 Germinal band, 70. 

 Germinal disc, in the Crayfish A thickening of the blastoderm, which 



indicates the ventral surface of the embryo, 105 ; in the Bird's ovum 



The lenticular mass which contains most of the protoplasm, 252, 256. 

 Germinal layers, in the Embryo Cell-aggregates, which precede the tissues 



in development (see Layers, Germinal, fate of). 

 Germinal spot The nucleolus of the nucleus (germinal vesicle) of an ovum, 



23, 34, 73. 



Germinal vesicle The nucleus of an ovum, 23, 34. 

 Giant-fibres, 66. 

 Gibbon, 338. 

 Gill A respiratory organ adapted for breathing the oxygen dissolved in 



water, 97, 115, 117, 166, 225, 315. 

 Gill-chamber, 86, 117. 

 Gill-filament, 117. 

 Gill slit, 141, 151, 155, 166. 

 Giraffe, 355. 

 Girdle, in the endoskeleton of limbs The part between the body and free 



limb. Shoulder (pectoral), 159, 185, 239, 280, 326; Hip (pelvic), 160, 



186, 239, 281, 327. 

 Gizzard A muscular part of the mid-gut, 57, 58, 242. 



