1936] Schultz: Keys to Fishes 199 



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. 



Articular. The bone of the mandible supporting the dentary and at- 

 tached to the quadrate. 



Articulate. Jointed ; said of soft fin rays. 



Atlas. The first vertebrae. 



Atrophy. Non-development. Diminutive in size. 



Attenuate. Long and slender, as if drawn out. 



Auditory capsule. The ventrolateral swelling of the skull, and con- 

 taining part of the inner ear. 



Axil, as "no scales in axil." The region under or behind the pectoral 

 fin base. 



Barbel. An elongate, fleshy projection, usually about the head. 



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



Base of skull. The lower or ventral portion of the cranium ; the ven- 

 tral outline of the parasphenoid is said to represent the "base 

 of the skull" in Sebastodes. 



Basioccipital. A median posteriorily and ventrally located bone of 

 the skull to which the atlas is attached. 



Basis cranii. A structure 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. 



Bicolor. Two-colored. 



Bicuspid. Having two points. 



Brachial ossicles. See Actinosts. 



Branchiae. Gills, the respiratory organs of fishes. 



Branchial. Pertaining to the gills. 



Branchiostegals. The bony rays supporting the branchiostegal mem- 

 branes, under the head of fishes and below the opercular 

 bones behind the lower jaw, and attached to the hyoid arch. 



Breast. The region on the ventral side of the head, anterior to the 

 ventral fins and posterior to the isthmus. 



Bristle. A stiff hair or hair-like structure. 



Buccal. Pertaining to the mouth. 



Caducous. Falling off early or easily. 



Caecal or coecal. Of the form or a blind sac. 



Caecum, (pi. caeca). An appendage of the form of a blind sac, con- 

 nected with the alimentary canal at the posterior end of the 

 stomach, or pylorus. 



