Catalogue of the Fishes of the Eastern Coast of North America from Greenland to Georgia

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Academy of Natural Sciences, 1861 - 63 páginas
 

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Página 25 - Professor Owen's Lectures on the Comparative Anatomy and Physiology of the Vertebrate Animals, delivered at the Royal College of Surgeons in 1844 and 1846.
Página 6 - The endo-skcleton (inside frame) is almost always osseous. The scapular arch is suspended from the skull ; the supra scapula generally connected with the mastoid, and paroccipital bones. The exo-skeleton (outside frame) is generally in the form of cycloid, or ctenoid scales, but sometimes the body is naked, and sometimes covered with bony scales, plates or spines. The optic nerves cross each other in their passage from their respective lobes to the eyes. * Catalogue of fishes of the eastern coast...
Página 24 - Each receives the streams of water for the aeration of the blood through short tubes, entering from a median canal which is below and distinct from the oesophagus, and which terminates behind in a closed wall, and, according to Professor Owen, communicates with the fauces anteriorly "by an opening guarded by a double membranous valve.
Página 11 - Cnryc/iium. body is entirely naked, and the arrangement of the muscles is very apparent. It is very doubtful whether this order truly belongs near to the preceding orders, and it is only provisionally retained here. By Sir John Richardson, in the valuable essay on " Ichthyology," in the Encyclopaîdia Britannica, it is placed as a third suborder of the Dermopteri of Owen. Until it is better known, we prefer to retain it among the Teleostei, to which, notwithstanding the rudimentary condition of its...
Página 22 - The bulbus arteriosus or aorta has a thick muscular coat, and is provided with at least two rows of semi-lunar valves. The intestine has a spiral valve. The males are provided with the so called " claspers," which are present as appendages to the posterior edge of the ventral fins.
Página 7 - Suborder PHYSOCLYSTI* (Bon.) scales, when present, are either ctenoid or cycloid ; there are rarely osseous plates. The anterior rays of the dorsal and anal fins, and the first ray of the ventrals are simple or spinous. The ventrals are generally more or less anterior. The lower pharyngeal bones are small and triangular, sometimes united, but generally distinct ; the teeth are implanted on the plane surface. The air-bladder never has a duct communicating with the intestinal canal. The group for which...
Página 15 - Lepidosiren, the opening of the ductus pneumaticus of the pulmonary sacs into the ventral face of the digestive canal. But we also find a similar arrangement in the species of the genus Polypterus, animals whose piscine characters and affinities have never been called in question.
Página 6 - The bulbus arteriosus^ has almost always only two opposite semilunar valves. The branchial apertures are represented by simple fissures on each side. There are four pairs of true and well developed branchial arches, each of which generally supports free branchiae ; an air bladder is generally present. The neutral fins vary in position, and are sometimes absent. This class embraces by far the largest proportion of existing fishes; and have been divided by Prof. G. into five "natural, and easily distinguished...
Página 8 - CharacinsJ- where all or some of them are ctenoid. The fins are mostly sustained by branched rays, only the first rays being sometimes simple. The ventral fins are always abdominal. The lower pharyngeal bones are separated, and almost always small and triangular, with the teeth on a plane surface. The air-bladder communicates by a duct with the mouth or intestinal canal. This suborder is almost сo- equal in extent with the Physostomi of Müller, the Cyprinoids being alone withdrawn.
Página 22 - They have the endo-skeleton or vertebral column, and skull cartilaginous, or, very imperfectly ossified. The exo-skeleton is developed in the form of placoid granules. The brain. is much more complex and highly developed, than in the true fishes ; the optic nerves are connected by a commissure, but do not cross each other. The bulbus arteriosus or aorta has a thick muscular coat, and is provided with at least two rows of semi-lunar valves.

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