970 



PISCES. 

 Fig. 505. 



Myology of the Perch. After Cuvier. 



men by strong fleshy origins covered with dense 

 aponeurosis. Above the pelvic arch they di- 

 vide into numerous tendinous slips which run 

 backwards in separate sheaths, each successively 

 approximating the middle line of the body, 

 where they are inserted on the dorsal aspect of 

 each vertebra as far as the extremity of the tail. 



The inferior lateral muscles, like the prece- 

 ding, take their origin in the lumbar region, 

 and present nearly the same arrangement, only 

 their tendons are much more slender than those 

 of the superior set. At their termination each 

 tendon bifurcates, allowing that appropriated to 

 the succeeding vertebra to pass through it so as 

 mutually to form sheaths to each other, so that 

 they are all, except the last, both peij'orati and 

 perforantes. 



Osseous Fishes have no special muscles ap- 

 pointed for the movements of the head, but in 

 the Rays there are three destined to this office, 

 one serving to move the head upon the trunk, 

 the other two raising and depressing the extre- 

 mity of their elongated snout. 



The former is situated upon the upper as- 

 pect of the body above the branchial cavity. It 

 arises from the vertebral column and from the 

 anterior portion of the pectoral zone. Its inser- 

 tion is into the posterior region of the head, 

 which it raises towards the back. 



Of the two muscles of the snout, the superior 

 arises also from the scapular cincture by a short 

 fleshy belly, from which a thin cylindrical ten- 

 don is given off. This runs in a mucous sheath, 

 above the branchiae to the base of the snout 

 where it is inserted, serving of course to raise it 

 upwards. 



The other is situated beneath the body within 

 the branchial cavity, where it arises from the 



anterior cartilages of the vertebral column, [t 

 runs obliquely outwards, and afterwards in- 

 wards, so as to describe a curvature, the con- 

 vexity of which is external. Its insertion is 

 almost entirely fleshy into the base of the ros- 

 trum, which it bends or curves towards the 

 belly. 



The muscles of the huge pectoral fins form 

 two thick fleshy layers, covering these limbs 

 both above and below, and dividing into as 

 many fasciculi as there are fin rays, into which 

 they are inserted. A similar arrangement exists 

 likewise in the ventral fins, the representatives 

 of hinder extremities. 



The muscles of the jaws in the cartilaginous 

 Fishes are more numerous than in those pos- 

 sessed of an osseous skeleton. The lower jaw 

 of the Skate is depressed by a large oblong 

 muscular mass, composed of straight parallel 

 fibres, which, taking its origin from the anterior 

 margin of the transverse cartilaginous belt that 

 sustains the pectoral fins, runs forward to be in- 

 serted near the centre of the inferior maxilla, 

 which it thus powerfully depresses. 



Two small muscles, one on each side, con- 

 tribute to the same effect. These are attached 

 in front near the commissure of the lips, and 

 running inwards, almost cross each other be- 

 neath the preceding, which is azygos ; there 

 they are attached partly to the skin, and partly 

 to the transverse cartilage. 



Those muscles which raise the lower jaw act 

 likewise upon the upper. One attached to its 

 lateral part mounts over the upper jaw, as over 

 a pulley, and runs to be implanted above the 

 upper jaw, which is here moveable, into the 

 base of the cranium. 



A second is broad and short. Its fibres are 



