ICHTHYOLOGY. 155 



Introduc of subcarbonate of lime. The animal matter is of two The anterior members, commonly called the pectoral Introduc- 

 . ^'° "" , kinds : — the one, of an azotised nature, forms the base of fins, consist of the shoulder, an osseous semicircle com- I'o"- 

 "~^l'~'^ t|)e cartiiage ; the other is fatty, in the form of a pervad- posed of several bones suspended above from tlie cranium ^'"Y"^^ 

 ing oil. The cartilage of fish bones differs from that of or the spine, and joined beneath to the corresponding 

 mammifera; and birds, in as far as it yields no gelatine portion of the otiier side. We can here also distinguish 

 when subjected to tiie process of boiling. The oil is certain bones analogous to the two pieces of the omoplate 

 composed chiefly of oieine, impregnated with an odorous of reptiles, to the humerus, and to the bones of the fore- 

 principle and a yellow colouring matter. The oil itself arm ; and further back there is usually a small projec- 

 is easily convertible into soap, and then produces oleic tion, composed of two pieces, which have been supposed 

 acid, glycerine, and a minute portion of margaric acid. to represent the coracoid bone, and even the clavicle. 



The skeleton of osseous fishes consists of the head ; What is more assured is, that the two bones which Cu- 



of the respiratory apparatus, having always a large bony vier compares to the cubitus and radius, bear on their 



development; of the trunk, including body and tail ; and margin a range of little bones, which seem to represent 



of members, that is, the pectoral and ventral fins. The those of the carpus, and which themselves support the 



vertical fins, viz. those of the back, anus, and tail, may rays of the pectoral fin, excepting the first of the latter, 



likewise be viewed as belonging to the trunk. which articulates directly with the radial bone. 



The head, possessing many more moveable parts than The posterior members, much more variable in their 

 that of the Mammalia, is subdivisible into a great many position than the corresponding limbs of the Mammalia, 

 regions, such as the cranium, the maxilla;, the bones and of which the external and moveable portions are 

 beneath the cranium and behind the jaws, and which aid named the ventral fins, project sometimes in advance of, 

 in their movement and suspension ; the bones of the oper- sometimes beneath, and sometimes behind, the anterior 

 cles, which open and shut the overtures of the bran- or pectoral members. They are composed of four bones, 

 chia;; the bones, almost exterior, which surround the of which the largest, which are likewise the most con- 

 nostrils, the eye, and the temples, or which cover a por- stant, being always placed in advance of the anus and of 

 tion of the cheek. the generative system, may be regarded as a sort of pu- 



In the majority of fishes the inter-maxillary bone forms bis, and bear upon a portion of their posterior margin the 

 the edge of the upper jaw, and has behind it the maxil- rays of the fin, without any smaller intermediate bones 

 lary, commonly called the mystax, or labial bone. A pa- which can be compared either to the femur, the tibia, 

 latine arch, composed of the palatine, of the two ptery- the peroneum, or tarsal bones. The rays of both the 

 gold processes, of the jugal, t3'mpanic, and squamous pectoral and ventral fins are likewise divisible lengthwise 

 bones, constitutes, as among birds and snakes, a kind of into halves, like those of the vertical fins before mention- 

 interior jaw, and provides posteriorly an articulation to ed. These rays, with the exception of the external ven- 

 the lower jaw-, which has usually two bones on each side, tral one of the Acanthopterygii {which is spinous), are al- 

 io the Chondropterygii, however, these various pieces are most always articulated, 

 greatly reduced in number. The skeleton of the Chondropterygii, such as sharks and 



Besides the apparatus of the branchial arches, the hy- skates, is composed of pieces consisting of no fibrous tis- 



oid bone carries on eacli side certain rays which support sue characteristic of bone. The interior continues in a 



the branchial membrane ; a kind of lid or clapper, com- cartilaginous state, and the surface alone becomes indu- 



posed of three bony pieces, the opercle, the sub-opercle, rated by the accumulation of small calcareous granules, 



and the inter-opercle, unites with that membrane to close which produce externally a stippled aspect. The form 



the great opening of the gills ; it articulates with the as of the cranium is similar to that of other fishes, but ne- 



tJ/mpam,aml plays on the piece called the pre-opercle. But, vertheless consists of only one enclosure, without sutures, 



like the parts before mentioned, this apparatus is likewise The face is very simple, with only two bones in the pala- 



wantingin many of the Chondropterygii. to-temporal arch; — the first descending from the crani- 



The trunk is composed of the vertebrje of the back uni, at the articulation of the jaws, — the other represent- 



and tail (for we can scarcely say that there is any neck, ing the upper jaw, and bearing the teeth. The maxillary 



and the sacrum is wanting) ; of ribs ; of the interspinal and inter-maxillary bones are merely rudimentary. The 



bones, which give support to the dorsal and anal fins ; under jaw has also but one bone (the articular) on each 



and of the rays of those fins, and of the caudal. These side, bearing the teeth ; of the others only a single ves- 



rays, whether branched and articulated, or simply spi- tige is discoverable, concealed beneath the skin of the 



nous, may be always divided lengthways into halves. lip. The opercular apparatus is wanting, but the hyoi- 



The vertebrae of fishes are characterised by the conical dean and branchial structure is very conformable with the 

 hollow on each of their faces. Double hollow cones are same parts in osseous fishes. Sharks have, moreover, op- 

 thus formed in the interval between two vertebrae, fill- posite to the external attachment of each branchia, a slen- 

 edbya soft membranous and gelatinous substance, which der bone, which may be regarded as the genuine vestige 

 passes from one void to another by means of an opening of a rib. The branchial system is situate further back 

 through each vertebra, and forms as it were a gelatinous than in osseous fishes, and hence the humeral girdle is 

 chaplet through the whole. They have, as in other ani- also more posterior. The spinal ribs, if they exist, are 

 mals, an annular portion in their superior part, for the usually very small, except in the sturgeons. In that ge- 

 passage of the spinal marrow. nus, indeed, the branchial system is in some respects inter- 

 Fish rarely possess a sternum properly so called, and mediate between the cartilaginous and osseous fishes, 

 when it does exist, it is formed of almost external pieces, Several bones of the head and shoulder are as hard as 

 which unite the inferior extremities of the ribs. stone, yet the spine is almost as soft as that of lampreys.' 



' For the sake of a more explicit comprehension of the principal portions of the osteological system of fishes, we have figured 

 (from Cuvier) the skeleton ot'tlie perch. We shall here subjoin the names of the bones, in reference to the engraved numerals. See 

 Plate CCXCVII. figs. 1, 2, 4, 5. 



Cranium : Principal frontal, 1 ; anterior frontals, 2 ; ethmoidal, 3 ; posterior frontal, 4 ; basilary, 5 ; sphenoid, 6 ; parietals, 7 ; 

 inter-parietal, 8 ; external occipital, 9 ; occipital lateral, 10 ; great ala, or temporal ala, II; mastoidean, 12; rupes, 13; orbitary 

 ala, 14; anterior sphenoid, 16; vomer, lU. Upper jaw : Inter-maxillary, 17; maxillary, 18. Nasal, sub-orbitury, and supia-temporal 

 bancs: First sub-orbitary, 19; chain of bones attaclied to the last named, and endini^ at the posterior frontal (these are conspi- 

 cuous in Trigla and Scorpaena), likewise numbered 19 ; nasal, 20 ; supra-temporals, 21. Puleiiue arch, or palatim-pUrygoidean and 



