378 VERTEBRATE ANIMALS OF THE UNITED STATES 



Falcate. Scythe-shaped; elongate, slender and curved. 



Falciform. Scythe-shaped. 



Fauna. The animals inhabiting a region. 



Femoral. Pertaining to the thigh. 



Femoral pores. A row of pores on the thigh of many lizards. 



Ferruginous. Reddish brown. 



Filament. A thread-like structure. 



Filiform. Thread-like in form. 



Fin-rays. The small bony or cartilaginous projections of the gill arches. 



Finnistemal. Referring to the pectoral girdle of frogs, the cartilaginous elements of which 

 are fused midventrally. 



Flipper. The fin-shaped legs of certain aquatic turtles and mammals. 



Fontanelle. An unossified space in a bone. 



Foramen. An opening. 



Forficulate. Deeply forked. 



Frontal bones. The bones forming the top of the head in front. 



Frugivorous. Fruit-eating. 



Fulcra. Spine-like projections of the fin-rays in certain fishes. 



Fulvous. Reddish-yellow; tawny. 



Furcate. Forked. 



Fuscous. Dusky. 



Fusiform. Spindle-shaped; tapering towards ends. 



Ganoid. A representative of the Ganoidea. 



Ganoid scales. Rhombic scales of many ganoid fishes. 



Gastrosteges. The transverse plates which cover a snake's belly; the ventral plates. 



Gills. The organs of respiration of a fish and of many amphibians. 



Gill-arches. The bony or cartilaginous arches which support the gills. 



Gill-clefts. The openings between the pharynx and the outside in which the gills are 

 located. 



Gill -rakers. A series of projections along the inner margin of certain of the gill-arches. 



Gill-slits. The gill-clefts. 



Glottis. The opening from the pharynx into the trachea. 



Granulate. Roughened; with granular prominences. 



Grinders. The molar and premolar teeth of rodents and some other mammals, the sur- 

 faces of which grind the food. 



Gular. Pertaining to the upper part of the throat. 



Hazel. Dark brown. 



Height. The vertical dimension of an animal. 



Heterocercal fin. An unsymmetrical caudal fin of a fish, the upper lobe being usually 

 longer than the lower and containing the backbone. 



Hibernate. To pass the winter in a torpid condition. 



Hirsute. Shaggy. 



Homocercal fin. A symmetrical caudal fin of a fish, the backbone ending at the base of 



the fin and not entering it. 

 Homologous. Having a common origin. 

 Hyoid. The bones which support the tongue. 

 Ichthyopsida. Fish-like vertebrates, those that breathe in the water at some time of their 



lives. 

 Imbricate. Overlapping, like the shingles on a roof. 

 Incised. Cut into; deeply notched. 

 Incisors. The front teeth. 

 Inferior. In a lower position. 

 Infraoral lamina. The toothed plate or ridge posterior to the mouth of a lamprey. 



