fTRUCTURE OF FISHES. 199 



appropriate for the general division or class. But, as 

 the flakes are arranged in distinct longitudinal rows, 

 these rows must be considered as orders. And, as couches 

 appears objectionable, I shall adopt series in its stead ; 

 distinguishing each by a word referring to its situation in 

 the animal, viz. the dorsal, vertebral, abdominal, and 

 Tcntral series. 



These series are composed of thin masses of muscle, or, They are dig- 

 as they are commonly called, flakes; which for the most P^^^^^ m ^akc* 

 part are thicker upon their outward edges, and become 

 wedge-shaped toward their interior attachments. Each 

 series is separated from the next adjoining by a membra- 

 nous partition, which is most apparent between the ver- 

 tebral and abdominal scries. 



The dorsal series {ff) arises from the back of the head. Particular de» 

 In its course it is terminated on the upper edge by the ^^'^^P^^^"* 

 bones, which support the single fins, and a membranous 

 septum : at this part the flakes are thin. Its lower margin 

 is bounded by the vertebral series, where the flakes be- 

 come gradually thicker. The first flake is composed of 

 longer fibres than the rest, and possesses more red b|ood. 

 Those succeeding it range obliquely backwards. They 

 are all joined together by cellular membrane, and shining 

 fasciae, which resemble the tendinous expansions in qua- 

 drupeds. 



Toward the middle of the fish the flakes are thicker, 

 and stand more perpendicular to the surface, becoming 

 oblique and thin as they approach the tail ; whilst the in- 

 tervening fasciae are most dense at each extremity. This 

 series consists of forty-five flakes, a number correspond- 

 ing with that of the spinous processes to which they are ' 

 attached, and which docs not vary with the growth of 

 the fish. 



The muscular fibres constituting each flake, run nearly 

 at right angles with its anterior and posterior surfaces, 

 and parcllel to the length and surface of the fish ; except 

 that their posterior extremities incline somewhat inwards. 



As the skull affords the ultimate fixed attachment of 



this series, and its moveable insertions are on the verte,* 



brae, and the tail, it follows, that its combined action is 



to bend the whole body and tail towards one side; or, if 



J)d % the 



