GLOSSARY OF TECHNICAL WORDS AND TERMS 



Abdomen. The belly; the ventral portion of the posterior region of the trunk. 



Abdominal. Pertaining to the abdomen; applied to the ventral fins of a fish when they are 

 posterior in position. 



Abortive. Incomplete; undeveloped. 



Acrodont teeth. Teeth which are situated along the edge of the jaw bone. 



Acimiinate. Tapering to a point. 



Acute. Sharp-pointed. 



Adipose. Fatty; thick. 



Adipose fin. A fleshy, spineless fin back of the dorsal fin in certain fishes. 



Adnate. Grown together; a fin which is attached along its lower edge as well as by its base. 



Adult. A mature, sexual animal. 



Adventitious. Coming from without; foreign. 



.^stivate. To pass the summer in a torpid condition. 



Air bladder. A large sac filled with air or some other gas lying beneath the backbone in the 

 body cavity of most fishes. 



Albinism. A more or less complete lack of pigment in the integument and eyes of an ani- 

 mal; opposed to melanism. 



Allantois. The embryonic respiratory organ of the higher vertebrates. 



Alveoli. Deep pits in a bone; the sockets of the teeth. 



Amnion. The protective envelope of the embryo of the higher vertebrates. 



Amniota. Those vertebrates possessing an amnion. 



Amniotic. Pertaining to the Amniota. 



Amphiccelous. Biconcave vertebrfe. 



Amphioxus. One of the most primitive chordate animals. 



Anadromous. Marine fishes which run up rivers to spawn. 



Anal. Pertaining to the anal region of the body. 



Anal fin. The median fin just behind the anus. 



Anal glands. Glands in connection with the anus which secrete an odoriferous fluid. 



Anal plate. The plate immediately in front of the anus in snakes. 



Analogous. Having a similar function. 



Anamnia. Those vertebrates which do not possess an amnion. 



Anchylosed. Grown firmly together. 



Anteorbital plate. The plate in front of the eye in snakes. 



Anterior. Toward the front end of an animal. 



Anus. The hinder opening of the digestive tract. 



Aorta. The main artery which carries blood away from the heart. 



Aplacental. Not having a placenta. 



Apodous. Without feet. 



Appendage. A projection from some part of the body, usually applied to the locomotory 

 appendages, the legs. 



Appendicular. Pertaining to the locomotory appendages. 



Aquatic. Living in the water. 



Arboreal. Living in trees. 



Arciferous. Referring to the pectoral girdle of toads, the cartilaginous elements of which 

 overlap midventrally. 



Articulate. Jointed. 



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