A GLOSSARY 



OF 



BIOLOGICAL, ANATOMICAL, AND PHYSIOLOGICAL 

 TERMS. 



A. 



Abdo'men (L. abdere, to conceal). In the Vertebrata, the 

 posterior part of the cavity of the trunk, which contains 

 the principal viscera ; in some of the Invertebrata, the 

 hinder part of the body. 



Abdomina'lia. A subdivision of the Crustacea, the members 

 of which have appendages on the abdomen, but none on 

 the thorax. 



Abducen'tes (L. ab, away from ; ducens, leading). The name 

 given to the sixth pair of nerves which supplies the ex- 

 ternal rectus muscle of each eye, by which muscle the 

 eyeball is rotated outwards, or away from the middle line. 



Abduc'tion (L. abduco, I draw away). The drawing away of a 

 limb from the middle line. 



Abduc'tor ter'tii interno'dii secun'di dl'giti (L. abductor of the 

 third internode of the second digit). A muscle found in 

 both manus and pes in Hylobates (one of the Anthropo- 

 morpha), which is not at present known in any other 

 mammal. 



Abioge'nesis (Gr. a, not ; bios, life ; gennesis, birth). The pro- 

 duction of living from not-living matter. Spontaneous 

 generation. 



Abo'masum (L. ab, away from, and omasum). The fourth 

 stomach of a ruminant, which leads from the third stomach 

 or omasum. 



Abo'ral (L. ab, away from ; os, oris, the mouth). The opposite 

 face in a star-fish to that which contains the mouth. 



Acale'phae (Gr. akalephe, a nettle). The jelly-fishes or sea 

 nettles. 



