314 PHILOSOPHICAL TRANSACTIONS. [anNO 1787. 



Slices of the animal part. In the bones of fishes this does not seem to be the 

 case, the earth in many fish being so united with the animal part, as to render 

 the whole transparent, which is not the case when the animal })art is removed by 

 steepina; the bone in caustic alkali : nor is the animal part so transparent when 

 deprived of the earth The bones are less compact than those of quadrupeds 

 that are similar to them. 



Their form somewhat resembles what takes place in the quadruped, at least in 

 those whose uses are similar, as the vertebrae, ribs, and bones of the anterior 

 extremities have their articulations in part alike, though not in all of them. The 

 articulation of the lower jaw, of the carpus, metacarpus, and fingers, are excep- 

 tions. The articulation of the lower jaw is not by simple contact either single or 

 double, joined by a capsular ligament, as in the quadruped ; but by a very thick 

 intermediate substance of the ligamentous kind, so interwoven that its parts move 

 on each other, in the interstices of which is an oil. This thick matted substance 

 may answer the same purpose as the double joint in the quadruped. 



The 2 fins are analogous to the anterior extremities of the quadruped, and are 

 also somewhat similar in construction. A fin is composed of a scapula, os humeri, 

 ulna, radius, carpus, and metacarpus, in which last may be included the fingers, 

 because the number of bones are those which might be called fingers, though 

 they are not separated, but included in one general covering with the metacarpus. 

 They have nothing analogous to the thumb, and the number of bones in each is 

 different ; in the fore-finger there are 5 bones, in the middle and ring-finger 7, 

 and in the little finger 4. The articulation of the carpus, metacarpus, and fingers, 

 is different from that of the quadruped, not being by capsular ligament, but by 

 intermediate cartilages connected to each bone. These cartilages between the 

 different bones of the fingers are of considerable length, being nearly equal to 

 ^ of that of the bone ; and this construction of the parts gives firmness, with 

 some degree of pliability, to the whole. 



As this order of animals cannot be said to have a pelvis, they of course have 

 no OS sacrum, and therefore the vertebrae are continued on to the end of the tail; 

 but with no distinction between those of the loins and tail. But as those vertebrae 

 alone would not have had sufficient surface to give rise to the musples requisite to 

 the motion of the tail, there are bones added to the fore-part of some of the first 

 vertebrae of the tail, similar to the spinal processes on the posterior surface. 

 From all these observations we may infer, that the structure, formation, arrange- 

 ment, and the union of the bones, which compose the forms of parts in this order 

 of animals, are much on the same principle as in quadrupeds. 



The flesh or muscles of this order of animals is red, resembling that of most 

 quadrupeds, perhaps more like that of the bull or horse than any other animal : 

 some of it is very firm ; and about the breast and belly it is mixed with tendon. 



