426 



INDEX — GLOSSARY 



Fossorial, 374. 



Fossorial mammals, 374. 



Fossula, 128, 131. 



Free cheeks of trilobites, 286, 287, 291, 



2q6. 

 Fringe-finned ganoids, 345. 

 Frogs, 353 ; see Anura. 

 Frond, stem and leaf united into one 



body, 46. 

 Frontal bone, growth of horns from, 398 ; 



in cat, 325 ; in fishes, 346 ; in reptiles, 



367. 

 Fruit, fossil, 37. 

 Fucus, 36, 109. 

 Fidicopiis lyellianus, 359- 

 Funafuti atoll, 38. 

 Fungi, 40; food-getting in, 29; geologic 



range of, 408. 

 Funnel, in Belemnites, 271 ; in cepha- 



lopods, 252, 255. 

 Furrow, glabellar in trilobites, 286, 287, 



293. 

 Fusulina, 89, 91 ; F. secalica, 91. 



Galesaurus, 356. 



Gametophyte stage, 43, 44 ; in ferns, 45 ; 

 in seed-plants, 56 ; in spermatophytes, 



56. 



Ganges, flood plain of, 5. 



Ganglion (plu. ganglia), a knot of 

 nervous matter ; in annulate worms, 

 14s ; in gastropods, 237 ; in mammals, 

 334; in pelecypods, 213. 



Ganodonta, 382. 



Ganoids, 345 ; fringe-finned, 345.' 



Ganoin, 345. 



Garpike, 347 ; tail fin of, 344. 



Gastral canals, 100. 



Gastric mill, 279, 280. 



Gastric vacuole in A mceba, 85. 



Gastroliths, see stomach-stones. 



Gastropods, 234-250 ; absence of shell 

 in, 243 ; air breathing in, 242, 243, 

 250 ; asymmetry in body, 241 ; asym- 

 metry in shells, 241 ; blood in, 242 ; 

 callus of, 243 ; carnivorous, 242 ; 

 columella of, 243 ; compared to 

 cephalopods, 260; determination of 

 fossil, 243 ; dextral shell, 241 ; diges- 

 tion, etc., see Busycon ; fossils of, 244- 

 250; geologic range of, 244, 409; 

 heart of, 242 ; heart beat in, 242 ; 



herbivorous, 242 ; inclosure of shell 

 within soft body, 243 ; nerve con- 

 nectives crossed, 237, 242 ; operculum, 

 of, 244 ; respiration in, 242 ; sight in, 

 243 ; sinistral shell, 241 ; smell in, 

 242 ; subdivisions of, 244 ; survey of, 

 241 ; terrestrial, 250 ; touch in, 242 ; 

 umbilicus of, 243 ; vegetable feeders, 

 242. 



Gastrotricha, 141. 



Gastrula, — that stage in the develop- 

 ment of an animal from the egg to 

 maturity, which is composed of two 

 layers of cells, the outer layer or ecto- 

 derm and the inner or endoderm ; this 

 latter lines the future digestive cavity. 

 In its primitive state the gastrula arises 

 somewhat as if the hollow, rubber ball- 

 like blastula were pushed in at one side 

 so as to bring the two walls into con- 

 tact, producing thus a two-walled 

 bag, loi ; in brachiopods, 186; in 

 crustaceans, 281, 283 ; in evolution, 

 112; in Hydrozoa, 1 1 1 ; in pelecypods, 

 216; in sponges, loi. 



Genal spine, 295. 



Generalized types, see also evolution ; 

 among insects, 318 ; anomodonts, 356 ; 

 Bactrites, 261 ; Condylarthra, 384, 385 ; 

 Creodonta, 379 ; Crossopterygii, 345 ; 

 in the Cycadofilicales, 60; Lyginoden- 

 dron, 60; Megatheriidae, 382; Rhyn- 

 chocephalia, 355. 



Generation, alternation of; see alterna- 

 tion of generation. 



Genesee formation, fossils from, 146', 

 geologic age of, 146. 



Genesis ; see evolution. 



Genital plate, 167, 169. 



Geologic Time Scale, 407. 



Gephyrea, 141, 142. 



Gibbon, 400. 



Gigantosaurus, 361. 



Gill-covers in the crayfish, 276, 277. 



Gill-sHts, branchial clefts, 323. 



Gills, of crayfish, 285 ; of crustaceans, 

 281-282, 285; of fishes, 339; of 

 gastropods, 235; of moUusks, 206; 

 of pelecypods, 209, 210-21 1, 210, 211. 



Ginkgo biloba, 69 ; ancient distribution 

 of, 70 ; motility of male cells, 69 ; 

 present isolation as to species, 69; 



