GLOSSARY 



257 



Epistome. A projection above the mouth as in Pectinatella. 

 Esophagus. The portion of the alimentary canal which leads back from 



the buccal cavity or pharynx. 

 Euglenoid. Similar to Euglena, especially in movements. 

 Exopod. The branch of the biramous appendage of an arthropod which 



is away from the midline of the body. 

 Exoskeleton. An outer covering, as a shell. 

 Exumbrella. The convex or aboral side of a medusa. 

 Eye spot. A pigment spot generally supposed to be photoreceptive. 



Femur. In an insect appendage, the third segment from the body of 

 the animal. 



Fission. Eeproduction by division. 



Flagellum. An elongated, protoplasmic, motile process of a cell. 



Flame cell. An excretory cell characteristic of certain invertebrates, 

 e. g., platyhelminthes, nemertines, rotifers and certain polychaetes. 

 It possesses a cavity continuous with the lumen of the excretory 

 duct. This cavity may contain a bundle of cilia or a flagellum. 



Food vacuole. In Protozoa, a temporary space in which food is di- 

 gested. 



Foot. Among invertebrates, a locomotor organ characteristic of mol- 

 luscs. 



Funiculus. A strand of tissue which connects the stomach with the 

 body wall in Bryozoa. 



Funnel. The tube through which water is expelled from the mantle 

 chamber by cephalopods. 



Ganglion. A group of nerve cells. 



Gastric filament. One of the filaments in the digestive cavity of Scy- 



phozoa. 

 Gastrovascular. Digestive and circulatory in function, as the gastro- 



vascular cavity or coelenteron of coelenterates. 

 Gastrozooid. Feeding individual in a hydrozoan colony. 

 Genital atrium. A cavity receiving the genital ducts, as in Bdelloura. 

 Genital gland. A gonad. 

 Genital plate. One of the plates bearing the external openings of the 



genital ducts in echinoderms. 

 Genital pore. The external opening of a genital duct as in the genital 



plate. 

 Gill. Aquatic respiratory organ. 



Gizzard. A heavy, muscular, grinding division of the alimentary canal. 

 Gonad. A gland which produces sex cells. 

 Gonangium. See Gonotheca. 



17 



