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



Head width. Measured at the widest part. 



Height. Vertical diameter. 



Heterocercal. Said of the tail of fishes when vertically unequal, the 



backbone deflected upward into the upper lobe. 

 Hispid. Rough with stiff hairs or bristles. 

 Holotype. See type. 

 Homocercal. Said of the tail of fishes when not externally unequal, 



the last vertebrae fusing into a more or less symmetrical plate, 



the hypural plate. 

 Humeral spine. A spine above the base of the pectoral fin, attached 



to the pectoral girdle and directed posteriorly. 

 Humerus. Bone of the upper arm. 

 Hyoid. Pertaining to the hyoid bone or arch. 



Hyoid apparatus. Formed by a series of bones supporting the tongue. 

 Hyomandibidar. A bone by which the posterior end of the suspen- 



sorium is articulated with the skull ; the supporting element of 



the suspensorium, the mandible, the hyoid apparatus, and the 



opercular apparatus. 

 Hypercoracoid. The upper of the two bones attached to the cleith- 



rum or clavicle, indirectly bearing the pectoral fin. 

 Hypurals. The modified plate-like last few vertebrae supporting the 



caudal fin rays. 

 Hypobranchials. Bones of the branchial arches below the cerato- 



branchials. 

 Hypocoracoid. The lower of the two bones attached to the clavicle 



behind. 

 Hypohyals. Small bones, usually 4, by which the respective sides of 



the hyoid apparatus are joined. 



-id (suffix). Indicating membership in a family, thus percid, a mem- 

 ber of the Percidae. 



-idae (suffix). The family name always ends in idae, as Percidae, 

 Cyprinidae, etc. 



Imbricate. Overlapping like shingles on a roof. 



Imperforate. Not pierced through. 



-inae (suffix). The subfamily name always ends in inae, as Pcrcinae, 



etc. 

 Inarticulate. Not jointed. 

 -ine (suffix). Indicating membership in a subfamily, thus percine, a 



member of the Percinae. 

 Incisors. Front teeth compressed to form a cutting edge. 

 Inferior pharyngeals. Synonymous with pharyngeals. Main bones 



of pharyngeal arch. 



