GLOSSARY 493 



Analogy. Structural resemblance, usually superficial, due to similarity 

 of functions; e.g., wing of Butterfly and Bird. See Homology. 



Anaphase. Period in mitosis during which the daughter chromosomes 

 move toward the respective centrosomes. See Telophase. 



Anatomy. The structure of organisms, especially as revealed by dissec- 

 tion. See Morphology. 



Antennae. A pair of appendages of the Arthropod head, sensory in 

 function. 



Anus. Terminal orifice of the alimentary canal. 



Aorta. A great trunk artery carrying blood away from the heart. See 

 Dorsal Aorta. 



Aortic Arches. Arteries arising from the ventral aorta and supplying 

 the gills in aquatic Vertebrates. Undergo many modifications in the 

 ascending series of air-breathing Vertebrates. 



Aphids. Small sucking Insects; e.g., the green Plant Lice of garden shrubs. 



Apopyles. Pores leading from the flagellated chambers to the gastral 

 cavity of Sponges. 



Artery. A blood vessel carrying blood away from the heart. 



Arthropoda. Phylum of Invertebrates. Includes the Crustaceans, In- 

 sects, Spiders, etc. 



Associative Memory. Representative cerebral activity of the higher 

 animals and Man, exclusive of reason which presumably is confined to 

 the latter. 



Aster. Radiations surrounding the centrosome during cell division. 



Autonomic System. System of outlying ganglia and nerves which com- 

 municates with the central nervous system via the roots of the spinal and 

 cranial nerves. Regulates nearly all the involuntary functions of the 

 body. Sympathetic system. 



Autotrophic. Power to synthesize food from inorganic substances. Green 

 plants (holophytic) secure the necessary energy from light, and certain 

 Bacteria by the oxidation of inorganic substances. See Holozoic. 



Axon. A nerve fiber conducting impulses away from the nerve cell body. 

 Dendrites conduct toward the cell body. See Neuron. 



Bile Duct. Tube which conveys the secretions (bile) of the fiver to the 

 small intestine. Usually unites with the pancreatic duct to form a com- 

 mon duct which enters the intestine. 



Binary Fission. The division of a cell, especially a unicellular organism, 

 into two daughter cells; e.g., in Paramecium. 



Binomial Nomenclature. The accepted scientific method of designating 

 organisms by two Latin or Latinized words, the first indicating the genus 

 and the other, the species; e.g., the Dog, Canis familiar is; Man, Homo 

 sapiens. 



