A Manual of Palaeontology for the Use of Students with a General Introduction on the Principles of Palaeontology

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1872 Excerpt: ...vertebrae--that is, of vertebrae the bodies of which are concave behind and convex in front. The entire spinal column is divisible into not more than two distinct regions, an abdominal and a caudal region. The abdominal vertebrae possess a superior or neural arch (through which passes the spinal cord), a superior spinous process (neural spine), and two transverse processes to which the ribs are usually attached. The caudal vertebrae (fig. 275) have no marked transverse processes; but in addition to the neural arches and spines, they give off an inferior or haemal arch below the body of the vertebrae, and the haemal arches carry inferior spinous processes (haemal spines). The ribs of a bony fish are attached to the transverse processes, or to the bodies, of the abdominal vertebrae, in the form of slender curved bones which articulate with no more than one vertebra each, and that only at a single point. Unlike the ribs of the higher Vertebrates, the ribs do not enclose a thoracic cavity, but are simply imbedded in the muscles which bound the abdomen. Usually each rib gives off a spine-like bone, which is directed backwards amongst the muscles. Inferiorly the extremities of the ribs are free, or are rarely united to dermal ossifications in the middle line of the abdomen; but there is never any breast-bone or sternum properly so called. proceeding from a common base, and all divided transversely into numerous short pieces. The soft rays occur in many fishes in different fins, but they are invariably found in the caudal fin or tail (fig. 275, c). The rays of the median fins, whatever their character may be, always articulate by a hinge-joint with the heads of the interspinous bones. Fig. 275.--Skeleton of the common Perch (Perciz JIuviatilis). / Pectoral fin; V ...