GLOSSARY OF TECHNICAL TERMS. 365 



Cere. Fleshy, cutaneous, or membranous covering of the base of the 



bill in certain birds, particularly the Owls, Hawks, and Parrots. 

 Cervical. Pertaining to the neck. 

 Chiasma. Crossing of the fibres of the optic nerve. 

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

 Ciliated. Fringed with eye-lash-like projections. 

 Cirri. Fringes. 

 Claspers. Organs attached to the ventral fins in the male of sharks, 



skates, etc. 

 Clavicle. The collar bone, or lower anterior part of shoulder girdle, 



not entering into socket of arm. 



Cloaca. A common opening of genital, urinary, and alimentary canals. 

 Commissure. The line on which the mandibles of a bird are closed. 

 Compressed. Flattened laterally. 

 Condyle. Articulating surface of a bone. 

 Conirostral. Said of a bill like that of a Sparrow ; conical in form and 



with the commissure angulated. 



Coracoid. The principal bone of the shoulder girdle in fishes ; other- 

 wise a bone or cartilage on the ventral side, helping to form the 

 arm-socket. 

 Costal folds. Folds of the skin (of a Salamander) showing the position 



of the ribs (costae). 



Coverts. Small feathers hiding the bases of quills. 

 Crest. In birds, any lengthened feathers abput the head ; elsewhere, 



any elevated or crest-like projection. 

 Crissum. The under tail coverts, in birds. 

 Ctenoid. Rough-edged, said of scales when the posterior margin is 



minutely spinous or pectinated. 



Culmen. The middle line or ridge of the upper mandible in birds. 

 Cuneate. Wedge-shaped ; said of a bird's tail when the middle feath- 

 ers are longest and the rest regularly shorter. 

 Cycloid. Smooth-edged ; said of scales not ctenoid, but concentrically 



striate. 



Deciduous. Temporary ; falling off. 

 Decurved. Curved downward. 

 Dentary. The principal or anterior bone of the lower jaw, usually 



bearing the teeth. 

 Dentate. With tooth-like notches. 

 Denticle. A little tooth. 



Dentirostral. Having the bill notched near its tip. 

 Depressed. Flattened vertically. 



Depth. Vertical diameter (usually of the body of fishes). 

 Dermal. Pertaining to the skin. 

 Desmognathous. United palate, as in the lower water-birds (Loons, 



Gulls, etc.). 



Diaphanous. Translucent. 



Diaphragm. Muscular septum between thorax and abdomen. 

 Diapophysis. Transverse process of a vertebra. 

 Digitigrade. Walking on the toes, like a dog. 



