GLOSSARY. 415 



Entozoa — Parasitic animals which live inside the bodies of other 



animals, 

 Epizoa — Parasitic animals which live outside the bodies of others. 

 EOLIS— A Mollusc of the Nudibranch order. (See Plate II., fig. 1.) 

 Epithelium— A delicate membrane covering mucous membranes, as 



the epidermis covers the skin. 



Ganglion — A centre of nervous matter from which nerves radiate. 



The spinal chord is a series of ganglia blended together. So is the 



brain. 

 Gasteropoda — Mollviscs which crawl on their ventral surface — e. g. the 



Slug, Snail, &c. 

 GoNlASTER— One of the Starfishes. 



Hepatic — Belonging to the liver. 



Hermaphrodite — Having both sexes combined in a single individual. 



Histological — Histology is the doctrine of the tissues ; and tissues 



are the webs out of which the organism is fabricated. Organs are 



composed of various tissues. 

 Homologue — The same organ in different animals, having identity of 



parts with variety in form and function. The wing of a bird is the 



homologue of a man's arm, and of a whale's fin. But a gill is the 



analogue of a lung, not the homologue. 

 Hydra — Fresh-water Polype. 



Larva — The insect before its transformation. 

 Larviparous — Producing offspring by Larvae. 

 LERNiEA — An order of crustacean parasites. 

 LiMAX — The slug. 



Medusa —Jelly-fish. 



Molluscs — A division of the animal kingdom embracing great vari- 

 eties — e. g. the Oyster, Cuttle-fish, Snail, &c. 



Morphological — Morj)hology is the doctrine of the changes of form 

 which organs undergo dmnng development. 



NaiS— A worm very common in ponds ; also found in salt water. 

 Neurilemma — The investing sheath of the nerve. 



Nudibranchs — An order of Gasteropod molluscs having their gills 

 exposed — e.g. Doris, Tritonia, &c. 



(Esophagus — The tube leading from the mouth into the stomach. 

 Ovary— The organ in which the eggs are formed. 



Parenchyma — The soft tissue of organs ; generally applied to that of 



glands. 

 Parietes — The walls of the different cavities of the body. 



