136 



BALiENOPTERIDiE. 



It has been suggested to me by a comparative anatomist of con- 

 siderable experience that perhaps the lateral processes of the cervical 

 vertebrse of this whale might be lengthened in the adnlt, and the 

 end of the upper and lower processes united into a broad expanded 

 plate as in the genus Physaliis. 



In the skeleton of the small foetus of Balcenoptera, only 9 inches 

 long, figured, by Esohricht in the ' Eoyal Danish Transactions ' for 

 1846, 1. 14. f. 2, the lateral processes of the second vertebra are very 

 nearly of the same shape as in the adult, forming a broad expansion, 

 with a perforation at its base. The cervical and other vertebrae of 

 this foetus seemed to agree, in all details of form, with the same 

 bones in the adult. 



I do not deny that the lateral process of the first cervical vertebra 

 may not be continued in cartilage, and be of the same form as that 

 of the genus Physahis ; but at any rate we have no proof, if this be 

 the case, that the cartilage at the end ever becomes ossified in this 

 genus any more than in the genus Megaptera, both genera agreeing 

 in the equality of the thickness and strength and shortness of the 

 lateral processes. 



Fig. 24. 



Second cervical vertebra of Benedenia Knoxii. 

 Extreme width 19 inches ; height 10 inches. 



The genera Megaptera and Benedenia have separate, short upper 

 and lower lateral processes, which are rather dilated and truncated 

 at the end, having an interrupted circular perforation between their 

 inner bases. It has been suggested that, in the latter genus at 

 least, the separated processes may be only the imperfectly developed 

 state of the broad lateral process of the genus Physalus, the end 

 that is wanting in the skeleton probably existing in the living animal 

 in the state of cartilage. Bnt if this should be the case (which I 

 much doubt), the form of the margin of the perforation and the per- 

 foration itself must undergo great change during the ossification of 



