7 
and mechanical Action of the Muscles of Fishes. 
range obliquely backwards. They are all joined together by 
cellular membrane, and shining fasciae, which resemble the 
tendinous expansions in quadrupeds. 
Towards 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 intervening 
fasciae are most dense at each extremity. This series consists 
of forty-five flakes, a number corresponding with that of the 
spinous processes to which they are attached, and which does 
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 pa- 
rallel 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 vertebras, and 
the tail, it follows, that its combined action is to bend the 
whole body and tail towards one side ; or, if the flakes con- 
tract partially, to give it a serpentine motion. To produce 
these effects all the other series co-operate. 
The superior external edges of the flakes of the vertebral 
series (gg) form acute angles with the inferior external 
edges of those of the dorsal series, the apices of which point 
towards the tail : the flakes are larger, but their number is 
the same. The lower margin of this series is bounded by 
the central membranous partition, which has already been 
noticed to be more conspicuous than the other longitudinal 
divisions, and it apparently admits of greater motion. 
The abdominal scries (hh ) is composed of flakes similar to 
the preceding. They range towards the tail, forming an angle 
