356 BULLETIN OF THE BUREAU OF FISHERIES 
Barbel. — An elongate, fleshy projection, usually about the head; also called whiskers; present in 
most catflshes. 
Bicuspid. — Having two points. 
Branchiae. — The gills. 
Branchiostegals. — Slender bones forming the support for the branchiostegal membranes, lying 
under the head and below the opercular bones. 
Canines. — Long, conical teeth. 
Cardiform. — Coarse, sharp teeth in the jaws of fishes. 
Carinate. — Keeled; having a single ridge along median line. 
Catadromous. — Running down; said of fish that descend to the sea to spawn. 
Caudal. — Pertaining to the tail. 
Caudal fin. — The fin on the tail. 
Caudal peduncle. — The region between the anal and caudal fins. 
Cephalic.- — Pertaining to the head; as cephalic fins, meaning fins on the head, as in some of the 
rays. 
Cirri. — Fringes. 
Claspers. — Organs attached to the ventral fins of male sharks and skates. 
Caecum ( plural caeca). — An appendage in the form of a blind sac, connected with the posterior end 
of the stomach or pylorus. 
Compressed. — Flattened from side to side. 
Ctenoid. — Rough-edged; said of scales when the posterior margin is spinous or pectinate. 
Cycloid. — Smooth-edged; said of scales when the posterior margin is not rough: scales showing 
concentric lines or striations. 
Deciduous. — Falling away or out. 
Decurved. — Curved downward. 
Depressed. — -Flattened vertically. 
Distal.— Remote from the point of attachment. 
Dorsal. — Pertaining to the back. 
Dorsal Jin. — The fin on the median line of the back. 
Emarginate. — Slightly notched at the end. 
Falcate.— Scythe-shaped; long, narrow, and curved. 
Filament. — Any slender, threadlike structure. 
Filiform. — Thread form. 
Fontanel. — An opening between the bones of the skull. 
Foramen. — A hole or opening. 
Frontal bone. — Anterior bone on top of head, usually paired. 
Fusiform. — -Spindle-shaped; tapering toward both ends. 
Ganoid. — A group of fishes characterized by having the body more or less completely covered with 
bony platelike scales. 
Gape.- — Opening of the mouth. 
Gill arches. — The bony arches to which the gills are attached. 
Gill openings. — Openings reaching to or from the gills. 
Gill rakers. — A series of bony projections placed along the inner edge of the gill arch. 
Gills. — Organs for breathing the air contained in water. 
Haemal spine. — The lowermost projection of a caudal vertebra. 
Heterocercal. — Term applied to the tails of fishes when vertically unequal, the backbone being 
deflected upward, as in the sharks. 
Homocercal. — Term applied to the tails of fishes when equal, the backbone extending to the middle 
of base of caudal, as in most common fishes. 
Imbricate. — Overlapping; said of scales that overlap like shingles in a roof. 
Incisors.— Cutting teeth, usually in front of jaws. 
Interorbital. — Space between the orbits or eyes. 
Isthmus.- — The region between the lower part of the gill openings. 
Jugular. — Pertaining to the throat; said of ventral fins when attached in advance of the pectorals. 
Keeled.— Having a ridge along the median line. 
