GLOSSARY OF TECHNICAL TERMS* 



Abdomen. Belly. 



Abdominal. Pertaining to the belly; said of the ventral fins of fishes when in 



serted considerably behind the pectorals, the pelvic bones to which the 



ventral fins are attached having no connection with the shoulder girdle. 

 Abortive. Remaining or becoming imperfect. 

 Actinosts. A series of bones at the base of the pectoral rays. 

 Acuminate. Tapering gradually to a point. 

 Acute. Sharp-pointed. 

 Adipose fin. A peculiar, fleshy, fin-like projection behind the dorsal fin, on the 



backs of salmons, catfishes, etc. 

 Air-bladder. A sac filled with air, lying beneath the backbone of fishes, corres- 



spending to the lungs of higher vertebrates. 



Alisphenoid. A small bone on the anterior lateral wall of the brain case. 

 Amphiccelian. Double-concave; said of vertebrae. 



Anadromous. Running up; said of marine fishes which run up rivers to spawn. 

 Anal. Pertaining to the anus or vent. 



Anal fin. The fin on the median line behind the vent, in fishes. 

 Anchylosed. Grown firmly together. 



Angular. A small bone on the posterior end of the mandible. 

 Antrorse. Turned forward. 



Anus. The external opening of the intestine; the vent. 



Arterial bulb. The muscular swelling, at the base of the great artery, in fishes. 

 Articular. The bone of the mandible supporting the dentary. 

 Articulate. Jointed. 

 Atlas. The first vertebra. 

 Atrophy. Nondevelopment. 

 Attenuate. Long and slender, as if drawn out. 

 Auditory capsule. The ventrolateral swelling of the skull. 

 Barbel. An elongated fleshy projection, usually about the head, in fishes. 

 Basal. Pertaining to the base ; at or near the base. 

 Basibranchials. A lower median series of bones of the branchial arches. 

 Basioccipital. A median posterior ventral bone of the skull to which the atlas 



is attached. 

 Basis cranii. Formed by shelves of bone developed from the inner sides of the 



prootics which meet and form a roof to the myodome and a floor to the 



brain cavity. 

 Bicolour. Two-coloured. 

 Bicuspid. Having 2 points. 



Brachial ossicles. Synonymous with actinosts, q. v. 

 Branchiae. Gills; respiratory organs of fishes. 

 Branchial. Pertaining to the gills. 

 Branchihyals. Small bones at base of gill arches. 

 Branchiostegals. The bony rays supporting the branchiostegal membranes, 



under the head of a fish, below the opercular bones, and behind the lower 



jaw. 



Buccal. Pertaining to the mouth. 

 Caducous. Falling off early. 

 Ccecal. Of the form of a blind sac. 



Caecum. An appendage of the form of a blind sac, connected with the aliment- 

 ary canal at the posterior end of the stomach, or pylorus. 



* In the preparation of this Glossary the authors are indebted to Mr. Edwin 

 Chapin Starks for valuable assistance. 



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