GLOSSARY OF TECHNICAL TERMS.* 



Abdomen. Belly. 



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



inserted con8ideral)ly behind the pertorals, the pelvic bones to which 



the ventral fins are attached having no connection with the shoulder 



girdle. 

 Abortive. Remaining or becoming imperfect. 

 Actinosts. A seiies of bones at the basf^ of the pectoral rays. 

 Acuminate. Tapering gradually to a jioiut. 

 Acute. Sharp-pointed. 

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



on the backs of salmons, catfishes, etc. 

 Adult. A mature animal. 

 Airbladder. A sac filled with air, lying beneath the backbone of fishes, 



corresponding to the lungs of higher vertebrates. 

 Alisphenoid. A small bone on the anterior lateral wall of the bi^ain case. 

 Amphicdlian. Double concave; said of vertebra". 

 Anadromous. Eunning 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. 

 A71tror.se. 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. 

 Atrojyhy. Noudevelopment. 

 Attenuate. Long and sleuder, 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 l>y 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. 

 Bicolor. Two-colored. 

 Bicuspid. Having 2 points. 



Brachial ossicles. Synonymous with actinosts, q. v. 

 Branchiiv. Gills; respiratory organs of fishes. 

 Jlraiirhinl. 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 iish, below the opercular bones, and behind the 



lower jaw. 



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

 Edwin Chapin Starks for valuable assistance. 



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