164 



ICHTHYOLOGY. 



Inrri'iluc- iMalacopter}'gii, may be conveniently subdivided accord- 

 ^ j^'""' ing to the position of the ventral fins, whether situate 

 "^^f""*"^ behind the abdomen, suspended to the apparatus of the 

 shoulder, or entirely wantinfj. This view furnishes us 

 with three fjreat orders, the Malacopterygu Abdomi- 

 NALES (such as pike, salmon, and herring), the M. Sub- 

 BRACHiATi (such as cod, haddock, and flat fish), and the 

 M. ApoDEs (such as eels). 



But such a basis of subdivision is altogether inapplicable 

 to the remaining group of ordinary fishes, viz. the Acan- 

 THOPTERYGii, which at present can only be placed to- 

 gether in a certain series of natural families. Fortunate- 

 ly, several of these families are possessed of characters 

 almost as precise as those which could be assigned to 

 genuine orders. It is, however, impossible to assign to 

 the families of fish the same marked gradation so percep- 

 tible among those of the Mammalia. Thus the Chon- 

 dropterygians are related to serpents on the one hand 

 by the organs of the senses, and in certain cases even by 

 the generative svstem ; while, on the other, they bear an 

 alliance to the Mollusca and worms in the occasional im- 

 perfection of their skeleton. 



Before proceeding with our systematic exposition of the 

 minor divisions, we shall present our readers with a sketch 

 of Baron Cuvier's views regarding the general character 

 and relations of certain groups. After forty years devot- 

 ed to the study of Ichthyology, that great observer be- 

 came convinced that no acanthopterygian species ought 

 to be mingled in classification with the fishes of other fa- 

 milies, as attempted by many of his predecessors; and he 

 also came to the conclusion that the acanthopterygian 

 order, which comprises about three fourths of the entire 

 class, contains the characteristic type, and is the most 

 accordant and homogeneous, even amid all the variations 

 which it undergoes. 



The acanthopterygian character prevails over all the 

 others, and these ought to be employed only as subservient 

 to it, and never in opposition ; but the extreme constancy 

 of the general plan, and the predominating influence of 

 the regulating character, render it a matter of greater diffi- 

 culty to apply precise and perceptible characters of a sub- 

 ordinate nature. It is thus that the various families of 

 the acanthopterygian order pass so insensibly from one to 

 another, that we are often at a loss to define the transition. 

 The family of Percidas, for example, which is essentially 

 distinguished from that of the Scianidae by its palatinal 

 teeth, comprises a group of some extent, and extremely 

 natural in its constr\tction, which yet contains a portion of 

 species possessed of those teeth, while the other portion is 

 without them. The same thing happens in the family 

 with mailed cheeks (joues cuirassees), the majority of which 

 are allied to the perches, — the others to the Scifenidse. 

 The sciaonoid genera themselves approach in part to the 

 ChaJtodontes in the scales which in several instances more 

 or less cover their vertical fins, and yet it is necessary to 

 assimilate them still more closely to the Sparidae, by rea- 

 son, in many other instances, of the entire absence of those 

 scales. 



The malacopterygian families are distinguished by 

 stronger and more obvious differences, and several of them 

 are not only natural, but subjected to fixed limits, so that 

 each, in its separation from the other, preserves within it- 

 self a great resemblance in details. This precision is so 

 sensible, that the majority of natural families established 

 by Cuvier in this part of the class had been already signa- 

 lised by Artedi as generic groups. His Siluri, Cyprini, 

 Salmones, CliipetE, and Esoces, may remain unbroken, 

 and there is even no inconvenience in distributing them 

 according to the position of the ventral fins, because in 

 those genera the character in question, however trivial in 

 itself) is constant ; but it is clearly impossible to preserve 



the distinction of jugular, thoracic, and abdominal fishes, In trod uc- 

 in the mode established by Linnaeus. It is, as Cuvier ob- li"" 

 serves, of small consequence, in fact, whether the ventrals 

 manifest themselves externally a little before or a little 

 behind the pectorals, or immediately beneath them ; but 

 the circumstance of importance, as connected with the 

 structure of the fish, is to ascertain whether the pelvis be 

 attached to the bones of the shoulder, or whether it is sim- 

 ply suspended in the muscles of the abdomen. To desig- 

 nate the fish belonging to the former category, the name 

 of Sub-brachians has been bestowed by Cuvier, and that 

 without any reference to the external position of the ven- 

 trals, — that circumstance being dependent on the greater 

 or less extent of the bones of tlie pelvis. To those of the 

 second category he leaves the older name of Abdominals. 

 Lastly, the term Apodes naturally designates the JMala- 

 copterygians destitute of ventral fins. 



Cuvier's systematic exposition of fishes commences with 

 the Acanthopterygians, which constitute in reality only a 

 single family of vast extent. He then places in succession 

 the various families of Malacopterygians, in the order in 

 which they seem allied to the preceding great division ; 

 but he guards the student from inferring that these rela- 

 tions follow only in a single line or series. If the abdomi- 

 nal Malacopterygians may be so arranged, and may even 

 be made to commence with those \vhich possess some 

 spiny rays, they are not followed in so natural a succession 

 by either the apodal or sub-brachian tribes. The Gadi, 

 for example, are as nearly related as any of the xlbdomi- 

 nals to certain species of the acanthopterygian order, and 

 there would be no reason for jjlacing them after the Abdo- 

 minals if the question were mooted respecting the station 

 they should hold in nature. If they are actually arranged 

 subsequent to the latter in our systems, it is because the 

 exposition of facts in a book necessarily requires a succes- 

 sive order. 



The spirit of the same observation is applicable to the 

 rest of the fishes ; — to those of which the upper jaw is 

 fixed (Pleclognalhi), — to such as have tufted branchiae 

 {Lopliobranchii), — and, above all, to the great and impor- 

 tant series of Chondropterygians, which terminate the 

 class. I', is indeed chiefly among those last mentioned 

 that we perceive the futility of whatever system seeks to 

 arrange the objects of creation in a single line. Several 

 of the genera alluded to, the rays and sharks, for example, 

 may be said to rise above the rank of ordinary fishes by 

 the com|)licated nature of some of their organs of sense, 

 and by that of the generative system, which is more fully 

 developed in some particulars than even that of birds ; — 

 while other genera of the same series, and at which we 

 arrive by graduated transitions, such as the Lampreys and 

 Ammocastes, become so simplified in their structure, that 

 they have even been regarded as affording a connecting 

 link between the class of fishes and that of the articulated 

 worms. The genus Ammoca-tes certainly possesses no 

 skeleton; and its muscular apparatus is attached solely to 

 tendinous or membranous supports. 



Let it not therefore be imagined, says Cuvier, that be- 

 cause one genus or family is placed anterior to another, it 

 is for that reason to be regarded as more perfect, or supe- 

 rior to those that follow. He alone will indulge in that 

 fond fancy, who piu-sues the chimerical project of ranging 

 beings in a single series, — a project, be it remembered, now 

 renoimced by jihilosophy. The further we advance into 

 the penetralia of the temple of nature, the more we shall 

 feel convinced that a falser notion was never entertained in 

 relation to natural history. Genuine systems view each 

 being not as intermediate merely to two others, but as 

 central among many ; — they show the «onderful radiations 

 that link it more or less inmiediately with the vast web of 

 organic life ; and it is by such extended views alone that 



