196 INVERTEBRATE ZOOLOGY 



Food vacuole : a globule of water containing food particles ; Paramecium, 



166 ; Vorticella, 169 ; Amoeba, 175. 



Front: the anterior median portion of the epicranium, 10. 

 Funiculus : a mesenteric strand connecting the stomach pouch with the 



body-wall in bryozoans, 80. 

 Funnel : the siphon of a cephalopod, 114. 



Ganglion: an aggregation of nerve cells; grasshopper, 16; crayfish or 

 lobster, 35 ; crab, 38 ; Daphnia, 51 ; Xereis, 60 ; earthworm, 68 ; mussel, 

 91; clam, 101; snail, 111; squid, 123; Molgula, 128. 



Gastrolith : a calcareous body sometimes present in the stomach of crusta- 

 ceans, 34. 



Gastro-vascular space : the central cavity in Cnidaria ; Hydra, 146 ; tubu- 

 larian, 150; campanularian, 156. 



Gastrula : a stage in the development of the embryo in which two cell 

 layers only are present, the ectoderm and the endoderm. 



Gena: the lateral portion of the epicranium in insects, 10. 



Genital plate: a sclerite at the posterior end of the abdomen in the male 

 grasshopper, 9. 



Giant fibers: three large fibers in the dorsal portion of the nerve cord in 

 the earthworm, 69. 



Gill : an organ for the breathing of air contained in the water ; crayfish or 

 lobster, 29; crab, 37; sow-bug, 41; amphipod, 43; Caprella, 44; 

 Nereis, 57; mussel, 87; clam, 97; squid, 117. 



Gill-filament: ciliated vertical ridges on the surface of the gills of lamelli- 

 branchs ; mussel, 88; clam, 98. 



Gizzard : a portion of the alimentary tract with thickened muscular walls, 65. 



Glochidium : the larval form of Anodonta and Unio which lives a parasitic 

 life in the skin of fishes, 91. 



Gonotheca: the cuticular outer covering of the blastostyle, 156. 



Green gland: the kidney of a malacostracan crustacean, 34. 



Haemal : pertaining to the blood system. 



Head : the anterior body-division of the higher animals. 



Heart: a muscular tube-like or sac-like organ which propels the blood; 

 grasshopper, 12 ; crayfish or lobster, 32 ; crab, 38 ; Daphnia, 51 ; earth- 

 worm, 64; mussel, 88; clam, 98; snail, 106; squid, 119; Molgula, 

 127; starfish, 138; sea urchin, 144. 



Hemimetabolic : larval development with incomplete metamorphosis in 

 insects. 



