200 University of Washington Publications in Biology [Vol. 2. 



Canines. The teeth behind the incisors — the eye teeth ; in fishes any 

 distinctly enlarged conical teeth longer than others. 



Cardiform teeth. Teeth coarse and sharp, and arranged like the 

 spikes on wool cards. 



Carinate. Keeled ; having a ridge along the middle line. 



Catadromous. Running down ; said of fresh-water species which 

 run down rivers to spawn in the sea. 



Caudal. Pertaining to the tail. 



Caudal fin. The fin on the tail of fishes. 



Caudal peduncle. The tapering portion of the body behind the base 

 of the last ray of the anal fin. Its length is taken from that 

 point to the base of the mid-caudal rays. The least depth of 

 the caudal peduncle is taken at its slenderest part. 



Cavernous. Containing cavities, whether empty or filled with mu- 

 cous secretion. 



Centrum. The body of a vertebra. 



Cephalic fins. Pertaining to fins on the head as in certain rays ; a 

 detached portion of the pectoral. 



Ceratobranchials. Bones of the branchial arches just below their 

 angle. 



Ceratohyal. One of the hyoid bones. 



Chiasma. The union of the trunks of the optic nerves, in ganoid 

 fishes. In teleostean fishes the optic nerves cross or interlace 

 without uniting to form a solid chiasma. 



Chin. The space between the rami of the lower jaw. 



Chondrocranium. The rudimentary cartilaginous cranial skeleton, 

 corresponding to the primitive skull of cartilaginous fishes, of 

 which traces remain in bony forms. 



Ciliated. Fringed with eyelash-like projections. 



Cirrus, pi. cirri. Fringes; tendril-like flexible tufts of skin; hair- 

 like. 



C las per s. Organs attached to the ventral fins in the male of sharks, 

 etc., the myxopterygia. 



Compressed. Flattened laterally or side to side. 



Conus arteriosus. A muscular and contractile bulb between the ven- 

 tricle and the root of the aorta. It is furnished interiorly with 

 one or more transverse rows of packet-shaped valves to pre- 

 vent a backward flow of the blood. 



Coracoid. The principal posterior bone of the shoulder girdle in 

 fishes supporting the pectoral radials. 



Cranial. Pertaining to the cranium or skull. 



Ctenoid. Rough-edged ; said of cycloid-like scales having the pos- 

 terior margin minutely spinous, or pectinated, or toothed. 



