GLOSSARY 



Pronunciations are indicated in tlie glossary as far as possible without the aid of 



diacritical marks, but the following symbols have been necessary: 

 H = the German ch; 

 N = the French nasal n; 



u = the French u, pronounced by shaping the lips for sounding long oo and the 

 tongue for long ee. 



Abiogenesis {ab' i o jen' e sis). The origin of living things from nonliving matter; 

 same as spontaneous generation. 



Absorption. The imbiding of a liquid by osmotic or capillar}^ action. 



Acanthocephala (a kan' tho scj' a la). A group of parasitic wormlike animals some- 

 times included with the Nemathelminthes. For definition see Chap. 19. 



Acetabulum {as' c tab' u lum). The socket on either side of the pelvic girdle for the 

 head of the femur. 



Acetylcholine. A substance produced by nerve endings of the craniosacral sj'stem 

 and serving to stimulate certain organs, to inhibit others. 



Acid. A substance which readily gives up hj'drogen ions, H+. 



Actinomorphes (ak' tin o mor' Jeez). A group of animals in Blainville's early classifi- 

 cation; animals with radiating parts, such as the starfish. 



Adaptation. Fitness for the environment. In a concrete sense, an adaptive struc- 

 ture, habit, or function. 



Adductor. One of the large muscles attached to the valves of a mussel shell, or the 

 corresponding muscle of a glochidium ; also, one of nvmierous muscles in other 

 animals which draw a structure toward the median axis. 



Adipose. Pertaining to fat. 



Adrenal. One of two or more ductless glands in close relation with the kidneys in 

 most vertebrates. 



Adrenalin {ad ren' al in). A hormone produced by the adrenal medulla. 



Adsorption. The adherence of molecules of gases or dissolved substances to the 

 surfaces of other bodies. 



Aeolosoma (e' o lo so' ma). A genus of worms, phylum Annelida, subclass Oligo- 

 chaeta. 



Afferent. Leading toward; said of nerve fibers which conduct impulses toward the 

 central nervous system. 



Aganides {ag' a ni' deez). A genus of extinct cephalopods with bent sutures of the 

 goniatite form. 



Agkistrodon piscivorus (ag Ms' tro don pis siv' o rus). A species of snake, the cotton- 

 mouth moccasin. 



Alanin {al' an in). A very simple amino acid. 



Alecithal (a les' i thai). Containing httle or no yolk; said of certain eggs. 



Altricial (al Irish' al). Hatched in a weak, helpless condition; said of certain birds. 



Alveolar gland {al ve' o lev). A gland in which the lumen is inflated at certain points. 



Alveolus (al ve' o Ivs). One of the microscopic air chambers to which the bronchioles 

 lead in lungs. 



Amblycorypha {atji' bli kor' i fa). A genus of katydids. 



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