136 ESCHRICHT AND REINHARDT 



at once show us that we have here to do with another part of the osseous system of the posterior 

 extremities, and it is then clear that it can only be interpreted as a femur. It is, moreover, in 

 perfect accord with this interpretation that the ossification of this bone had already proceeded so 

 far in the newborn young one at a time when not the slightest nucleus of ossification had as yet 

 been formed in the pelvic bone. The flat, obtusely triangular, and smaller subsidiary bone may, 

 perhaps, from its situation, be most justly considered as a rudiment of the leg proper. 



In the forty-four and a half feet long whale the pelvic bone was on the one side eighteen 

 and a half inches, in the other nineteen and a quarter inches long, of which the posterior portion 

 measured about two thirds ; the latter {a) is, moreover, flattened, especially posteriorly, and here 

 souiewhat more than two inches broad, whereas the anterior piece (r/) was quite cylindrical, and 

 only one inch in diameter. In the newborn animal the same bone had only a length of two and 

 a half inches, making, accordingly, in this period of its age, only one sixty-second of the whole 

 length of the animal, whereas in the full-grcmi animal it made about one twenty-eighth of the 

 same. The femur [b) was in the latter eight inches long, almost cylindrical in its upper part, and 

 neariy two inches in diameter; at its inferior extremity it was much compressed, and four inches 

 broad ; in the cub it had, on the whole, a similar form, but was only two inches two lines long ; 

 the leg (c), finally, was much compressed in the full-grown specimen, four inches long, and about 

 two inches broad at its upper end ; whereas in the young animal it was about three quarters of 

 an inch long, nearly cyhndrical, its length several times greater than its thickness, and, besides, 

 attached in such a manner to the inferior end of the femur that it formed an angle with it, having 

 its free point turned obliquely backwards and downwards. 



When once it has been determined that the subsidiary bones of the pelvis of the Greenland 

 whale must be considered as rudimentary hind legs hidden in the flesh, it is obvious that this 

 interpretation must necessarily be transferred to the single pair of subsidiary bones found in the 

 hump-back, even if no one should in future succeed better than hitherto in finding still another 

 pair. We should, finally, feel inchned to suppose that a pair of similar subsidiary bones, as rudi- 

 ments of the hind legs, may be pointed out in the other rorquals also, though they have not been 

 found in the fin-whale foetuses (Balænoptera rostrata) hitherto examined ;^ on the other hand, 

 we are fully convinced that nothing corresponding is to be found in any of the hitherto more 

 carefully examined toothed-whales. 



It is evident that the presence of hind limbs, however rudimentary, in the whalebone- 

 whales, and their absence in the toothed-whales, cannot but infiuence our opinion about the 

 relative positions of these two cetaceous animals in the system ; and we shall accordingly add 

 a few words on this subject. 



Most zoologists have agreed in considering the toothed-whales to be nearer, the 



[' In a large male specimen of the common fin-whale {Physalus antiquorum. Gray ; Pterobalæna 

 communis, Esctr.) stranded in Pevensey Bay, in November, 1865, the femur was represented by an 

 oval cartilaginous nodule, an inch and a half in length, attached by a ligament to the pelvic bone. See 

 'Proceedings of the Zoological Society,' November 28th, 1865. W. H. 'P? 



