GLOSSARY 



abdomen. The portion of the body between thorax and pelvis. 



abducens. The sixth cranial nerve. 



abduction. The withdrawal of a part from the median plane. 



aberrant. Wandering from the usual. 



abnormality. Deviation from the normal. 



abomasum. The fourth stomach of a ruminant. 



aboral. Opposite to the mouth. 



abortion. Expulsion of a fetus before it can live. 



acetabulum. The socket in the coxal bone in which the head of the femur articulates. 



acidophilic. Easily stained with acid dyes. 



acidosis. Reduction of alkali reserves in the body. 



acinus. A grape-like terminal subdivision of a gland or lung. 



acoelomate. Without a body cavity (coelom) . 



acrania. Chordate animals without a brain-case. 



acrodont. With teeth fastened to edge of jaw and not lodged in sockets. 



acromegaly. A disease which involves an enlargement of bones due to over-functioning 



of pituitary gland. 

 acromion. The lateral extension of the spine of the scapula. 

 adduction. The act of drawing a part towards the median plane. 

 adenoid tissue. Lymphocyte-forming tissue. 



adrenal (suprarenal) gland. An endocrine organ located near the kidney. 

 adrenin. The suprarenal medullary hormone. 

 afferent. Centripetal, conveying towards the center. 



after -birth. Extra-embryonic membranes discharged from uterus after the child is born. 

 air bladder (sac). Respiratory or hydrostatic organ in fishes. 

 ala cinerea. The vagal eminence which projects into the fourth ventricle. 

 alar plate. The dorso-lateral portion of the embryonic neural tube. 

 alisphenoid. That part of the embryonic cartilage cranium which forms most of the 



great wing of the sphenoid. 

 allantois. A hollow outgrowth of the embryonic hind-gut. 

 alveolus, i. A tooth-socket. 2. A terminal acinus of a gland. 3. A respiratory sac 



of the lung. 

 ameloblast (adamantoblast). A cell which secretes enamel. 

 ammocoetes. The larval stage of Petromyzon. 

 amnion. The liquid-filled sac which encloses the embryos of reptiles, birds and 



mammals. 

 amniota. The animals the embryos of which are enclosed in an amnion. 

 amphicoelous. Biconcave like the centrum of a fish vertebra. 

 ampulla. A flask-like dilatation. 



amylopsin. A starch-splitting enzyme secreted by the pancreas. 

 analogy. Resemblance based on similarity of function. 

 anamnia. Vertebrates the embryos of which lack an amnion. 

 anastomosis. The communication of two vessels or connexion of two nerves, 

 angioblast. One of the cells from which blood and blood vessels develop. 



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