364 GLOSSARY OF TECHNICAL TERMS. 
Arboreal. Living in trees. 
Arterial bulb. The muscular swelling, at the base of the great artery, 
in fishes. 
Articulate. Jointed. 
Artiodactylous. Even-toed (toes 2 or 4). 
Atrophy. Non-development. 
Attenuate. Long and slender, as if drawn out. 
Auricle. The large lobe of the external ear; also, one of the chambers 
of the heart. : 
Barbel. An elongated fleshy projection, usually about the head, in 
fishes. 
Basal. Pertaining to the base ; at or near the base. 
Basipterygoid. Bones developed in the palatine arch in some birds. 
Beak. The bill of birds, or (in other animals) any beak-like structure. 
Bend of Wing. Angle at the carpus when the wing is folded. 
Bicolor. Two-colored. 
Bicuspid. Having two points. 
Booted. Said of the tarsus in birds, when its scales coalesce and form 
a continuous envelope, as in the robin. 
Branchie. 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 mem- 
branes, under the head of a fish, below the opercular bones, and 
behind the lower jaw. 
Bristle. A stiff hair, or hair-like feather. 
Buccal. Pertaining to the mouth. 
Caducous. Falling off early. 
Cacal. Of the form of a blind sac. 
Caecum. An appendage of the form of a blind sac, connected with the 
alimentary canal. 
Calcareous. Containing or composed of carbonate of lime. 
Canines. The teeth behind the incisors, — the “eye-teeth” ; in fishes, 
any conical teeth in the front part of the jaws, longer than the 
others. 
Carapace. The upper shell of a turtle, usually composed of bony plates 
covered by horny scales. 
Cardiform (teeth). Teeth coarse and sharp, like wool-cards. 
Carinate. Keeled; having a ridge along the middle line. 
Carotid. The great artery running to the head. 
Carpus. The wrist. 
Caudal. Pertaining to the tail. 
Caudal fin. The fin on the tail of fishes and whales. 
Caudal peduncle. The region between the anal and caudal fins in 
fishes. 
Cavernous. Containing cavities, either empty or filled with a mucous 
secretion. 
Cephalic fins. Fins on the head of certain rays a detached portion of 
"the pectoral. 
