VIKWS OK NATinr. rONTKASTKI). 11 



Externally, the pectoral fins do look at lirst sight very 

 much alike, hut you will on lookint; closer perceive that tus 

 in the tail lin, tiie fish's jn^-loral has rays visible externally 

 connected hy a thin mciiihranc. while none such arc visible 

 in the whale's lin. 



On taking;- the Uesh I'roui these i)ectoral lin>, and layin;; 

 bare the bones, you will at once perceive how utterly unlike 

 the framework of the limbs arc. in our two types— the jior- 

 poisc and the swordlish. 



In the porpoise we hav(> not the least ditiieulty in at 

 once recognizing; the bones corresponding to the linger 

 bones and metacari)al bones of man and quadrupeds ; next 

 Ave also plainly see bones answering to the carpal or wrist 

 bones; then there are two bones evidently comparable with 

 the Viones of the forearm, that is, the radius and ulna ; and 

 tinallv. next to the body, we see a single bone which is 

 plainly the c<|uivalcnt of the arm-bone or humerus of man. 

 Connected with the arm we lind a wide; Hat bone above, 

 and this, it is easily perceived, answers to the scapula or 

 shoulder blade. Unlike then as the pectoral tin of a 

 whale seems to be externally to the fore limb of man or 

 quadrupeds, it is very much alike in the skeleton. 



Now, let us turn to the fish's pectoral fin and its connec- 

 tions, and .see how different they are from the whale's. Let 

 us take a salmon's fiii and compare it, or rather contrast 

 it with the whale's. In the; salmon, far from iinding great 

 similarity between its parts and the porpoise's, we meet with 

 great difHculty in seeing any approximate agreement even : 

 lin ravs are first noticeable which are quite unlike digits or 

 fing(>r bones; at their ixise are four loiigi-h and ncarlv 

 parallel but diverging bones, which remind us somewhat of 

 metacar[)als, and serve as a sort of peduncle to tlu; lin. 

 Next wc find a chain of bones extending from the sides of 

 the skull behind, and uniting below with its fellow of th(^ 

 opposite side ; the pair are known as the shoulder ginlle, 

 or scapular arch ; and remind us somewhat of the wish- 

 . bone or clavicles of a fowl. To the inside of the largest of 

 these bones we see attached thriM l....,,-: wbieh intervene l)e- 



