1936] Schultz: Keys to Fishes 213 



Type. The particular specimen upon which the original description 

 of a species was based or the species upon which was based the 

 genus. 



Type locality. The particular place or locality at which the type was 

 collected. 



Ultimate. Last or farthest. 



Unicolor. Of one single color or shade. 



Vent. The external opening of the alimentary canal. 



Ventral fins. Paired fins corresponding to posterior limbs, or pelvics. 



Ventral fins, I, 5; I, 4 ; I, 2, etc.; one spine (Roman) and five soft 

 rays (Arabic), etc. 



Ventral plates. A row of plates along the belly between throat and 

 vent. 



Ventricle. One of the thick-walled chambers of the heart. 



Versatile. Capable of being turned either way. 



Vertebra. One of the bones of the spinal column. 



Vertebrae, Abdominal. Anterior vertebrae which occur dorsal to the 

 body cavity and to which the ribs are attached. They lack the 

 haemal arch and canal, and the haemal spines on their ventral 

 sides. 



Vertebrae, caudal. Posterior vertebrae which possess an arch, canal 

 and spine on the ventral side. 



Vertical. Up and down or dorso-ventrally. 



Vertical fins. Fins on median line of the body ; median fins, the dor- 

 sal, caudal and anal. 



Villiform. Said of the teeth of fishes when slender and crowded in- 

 to velvety bands, or compact patches. 



Viscous. Slimy. 



Viviparous. Bringing forth living young. Usually the mother con- 

 tributes food to the growth of the embryos. 



Vomer. In fishes, the front part of the roof of the mouth ; a bone ly- 

 ing immediately behind the premaxillaries, and usually bearing 

 teeth. 



Width. The width of a fish is taken at the widest part of the body. 



Weberian ossicles. A chain of small bones developed in connection 

 with the modified anterior vertebrae and connecting the air blad- 

 der with the ear in the Ostariophysi, such as suckers, carps, cat- 

 fishes, minnows, chubs, etc. 



Zygapophyses. Points of bone affording to the vertebrae more or 

 less definite articulation with each other. 



