GLOSSARY 



Algae, simple chlorophyll-bearing plants most of which live 



entirely submerged in water. 

 Anterior, front or head end. 

 Asexual, reproduction by other means than eggs and sperm 



cells, e. g., budding as in hydra. 

 Auricle, a chamber of the heart which receives blood from 



the veins; an ear-like lobe on a planarian. 

 Axolotl, a larva of A mby stoma tigrinum which matures sexually 



without changing its larval form. Found only in the 



southwestern United States. 



Balancers, processes in front of the gills of certain tailed am- 

 phibians, as in salamander larvae. 



Barbel, whisker-like feelers about the heads of some fishes, 

 e. g., the common bullhead. 



Brackish, water which is partly salt and partly fresh. 



Bryozoans, plant-like animals living in colonies, e. g., Crista- 

 tella. 



Calcareous, limy or containing calcium carbonate. 

 Carapace, hard upper shell of turtles or of cr^ustaceans such as 



crayfishes and lobsters. 

 Carnivorous, eating animal food. 

 Chitin, horny substance of the skeletons of insects and some 



other arthropods. 

 Chlorophyll, green coloring matter of plants. 

 Cloaca, a cavity in the body of vertebrates into which the 



intestine, urinary, and reproductive tubes open; not 



found in most mammals. 



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