The rod and the gun - 1840 Author:James Wilson Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: SECTION IV. . The Osteology of Fishes. The most important characters of the sides of the head are derived from the pre-opercle, and the adjacent parts which ... more »form the gill-covers,—that is the opercle, the sub-opercle, and the inter-opercle. The head of fishes usually consists of about sixty bones—the amount being sensibly greater in such species as have the upper maxillary subject to divi- CRANIUM OF PERCH. sion. The accompanying cut of the cranium of the perch, with the subjoined enumeration of the parts, will suffice to illustrate the subject with greater rays, whether branched and articulated, or simply spinous, may be always divided lengthways into halves. The vertebrae are characterised by the conical hollow on each side of their faces. Double hollow cones are thus formed in the interval between two vertebrfe, filled by a soft membranous and gelatinous substance, which passes from one void to another by means of an opening through each vertebra, and thus forms, as it were, a gelatinous chaplet through the whole. As in the other vertebrated classes, there is an annular opening through the superior portion, for the passage of the spinal marrow. Fish rarely possess a sternum properly so called, and when it does exist, it is formed of almost external pieces, which unite the inferior extremities of the ribs. The anterior members, of which the external portion is commonly called the pectoral fin, 53a, consist, in the first place, of a suite of bones on. each side immediately behind the orifice of the gills, and which form a kind of frame on which the opercle rests when closed. These bones, usually attached to the head above, and uniting together below, form an osseous belt which almost encircles the body. Their inferior symphysis unites by ligaments to the tail...« less