GLOSSARY 



Clypeus, the skeletal plate above the upper lip or labrum, in 



insects. 

 Coelenteron, food cavity in hydra and related animals. 

 Crustaceans, animals with jointed bodies and appendages 



and a limy skeleton. 

 Ctenoid, rough edged, said of the scales of fishes. 



Dermis, an inner layer of cells in the skin of vertebrates. 



Desmid, single-celled green plants apparently divided into 

 two parts by a light band. 



Diatom, minute single-celled plants which are characteristical- 

 ly golden brown. 



Dorsal, on or toward the back. 



Elytra, homy front or outer wings of beetles. 

 Entomostracan, a minute crustacean, e. g., Cyclops. 



Fertilization, the union of an egg cell and a sperm cell, fonning 



a new individual. 

 Formalin, a solution of formaldehyde used as a preservative. 



Gemmule, a capsule of sponge cells which live over the winter 

 and from which a new colony grows in the spring. 



Gills, organs by which animals can breathe in water. 



Glochiditmi, a larval mussel which lives as a parasite on the 

 skin of fishes. 



Haemophilia, an hereditary disease, in which the blood does 



not clot properly on exposure to air. 

 Hermaphrodite, having both male and female reproductive 



organs in one individual; true of hydra, earthworms, and 



many other animals. 

 Hibernate, to pass the r.'inter in an inactive dormant state. 

 Hydranth, one of the individuals which takes food in a 



colony of hydra-like animals. 



Imago, an adult, sexually mature insect. 

 Intemode, the part of a plant stem between the points from 

 which leaves spring forth. 



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