VIKWS nV NAT! Ki: < • >.NrK ASTKI). 9 



peculiar organ, inserted at the end of tlu; vertebral column, 

 and has a frame work of bones, developed amund the last 

 vertebra^ and appended to them. 



Before proceeding further to discuss the character of the 

 caudal fin of a whale, let mo call your attention to the fins 

 which are developed under the belly or middle of the body 

 in the carp and trout, and although absent in the sword- 

 fish, in ordinary lishes present. You will lind nothing eoi-- 

 responding to these in ]iosition in the whales, but I will now 

 attempt to show that these tins, which are called ventral 

 fins, inserted under the back, far forward, are represented 

 by the flukes of the tail of the whale, which must, therefon;, 

 be entirely different from the tail of a true fish. But how 

 can this be ? 



You are all acipiainted with the external appearance of 

 the seal, in which the posterior feet are obviously present, but 

 are thrown far backward, and are to a great extent horizontal 

 beyond the body. Now, imagine these fins, flippers, or feet, 

 whatever you may call them, with the bones atrophied, or 

 greatly decreased in size, and the integuments and soft tissues 

 greatly hypertrophied, that is, enlarged, and you will* see 

 that no great diflercnce exists between such fins hori- 

 zontally extended backward, and the flukes of the whale. 

 In fact, it is known, not only from anatomical, but from 

 embryological and ])aleontological data, that the tail of a 

 whale is essentially the result of an excessive development 

 of the integuments surrounding the posterior feet, and the 

 atrophy, or diminution of, or even in some cases the entire 

 loss of the posterior limbs, so far as the bones are concerned. 

 But the bones of the posterior limbs are not absent, or even 

 insignificant, in all si)ecies of whales. In the right whale 

 (that whence the whalebone is derived) we have not only the 

 pelvic or haunch bones, but also the proximal bones — those 

 next to the pelvic — developed ; that is, we have not only the 

 bones representing those which constitute the pelvis in man, 

 but we also have other bones connected with these boners 

 which represent the femur or thigh bone, and the .succeed- 

 ing or leg bones. Those bones are d.-veloped still more in 



