z8o INDEX. 



Gasteromycetes, characters of the family, i. 267 

 Gastropoda, structure of the shells of, ii. 234 



structure of the animal, ii. 235 



tongue of the, ii. 239 



Gelidiaceae, structure and mode of propagation of, i. 238 

 Gelidium corneum, structure and mode of propagation of, i. 238 



form of, i. 243 



Gems, crystals of, formed artificially by electricity, i. 74 

 Geranium, amount of radiant heat absorbed by the perfume of, i. 44 

 Glass, a non-conductor of electricity, i. 32 



property of, in regard to the transmission of light, i. 36 



impervious to chemical solar rays, i. 63 

 Gleicheninese, sporangia of, i. 34 



structure and habitat of, i. 344, 360 

 Globigerina bulloides, form of, ii. 28 

 Globigerina, structure of the genus, ii. 40, 41 



Globigerinae, abundance of at vast depths in the ocean, ii. 49-51 

 Globigerinidse, characters of the family of, ii. 40 

 Glycerine, chemical combination forming, i. 97 

 Glyphidei, characters of the order, i. 309 

 Glucinum, i. 4 

 Gold, colour of, in reflected and in absorbed light, i. 35, 36 



crystals of, formed artificially by electricity, i. 74 

 Gonidia, propagation of diatoms by, i. 202, 204 



of lichens, i. 300 

 Goniometer, i. 38 



Gorgonia graminea, structure and habitat of, ii. 124, 125 

 Gorgonia verrucosa, structure, habitat, and mode of reproduction of, 



ii. 124 

 Gorgonidse, structure and mode of reproduction of, ii. 123, 124 



the three natural groups of, ii. 124 

 Gracilaria compressa, i. 239 

 Gracilaria lichenoides, or Ceylon moss, i. 239 

 Gracilaria armata, mode of reproduction of, i. 230 

 Graminacese, structure and mode of reproductiou of, i. 385, 386 

 Grammatophora serpentina, structure and development of, i. 197 

 Graphidei, characters of the order, i. 308 



habitat of the, i. 309 

 Graphite, form of the crystals of, i. 15 

 natural, little or no porosity of, i. 112 

 porosity of artifical graphite, i. 112 

 Grasses, silica in the stalks and leaves of the, i. 17 



