STRUCTURES OF TELEOST I4I 
General Anatomy 
In the Teleost (Fig. 145) the shortened and muscular 
body appears admirably adapted to the conditions of 
aquatic motion. Anteriorly it is broad and deep, its 
trunk muscles firmly attached to the bony prongs of the 
enlarged base of the skull, DCR, and to the solid, compact, 
calcified vertebre, V, and their stout processes. The 
fish’s tapering sides are encased in horn-like cycloidal 
scales, CS, a light, flexible armour, whose elements over- 
lap, defending every point, and whose smooth and slime- 
coated surface provides the least possible resistance to 
motion. The fins, D, C, A, PF, VF, are light and strong, 
erectile and depressible; their rays are thin, narrow, spine- 
like, strong; they are entirely dermal, their cartilaginous 
supports sinking within the body wall, RB. The caudal 
is large and fan-shaped (homocercal), its crowded rays 
providing admirably its needed strength; its stout basal 
supports, compacted beneath the tip of the notochord, VC, 
show that its form is modified heterocercy. The pectoral 
fin, PF, has now taken its position high in the side of the 
body ; its basi-radial supporting elements are reduced to a 
proximal row of a few small irregular plates. 
The skeleton is completely calcified. The vertebral axis 
has undergone entire segmentation, the notochord persist- 
ing only between the cup-shaped faces of the centra; the 
vertebral arches and processes have merged with the 
centra, and those of the hinder region, WV, H, with prob- 
ably the basal fin supports.as well. Ribs, X, usually with 
intersupporting processes, strengthen the walls of the 
visceral cavity, and represent calcifications of the myocom- 
mata, rather than transverse processes of the vertebrz. 
The skull is formed of compact bony elements ; its carti- 
