106 



PROFESSOR STRUTHERS. 



region, and greater in the lumbar region, than in Megaptera. "While 

 in Megaptera the slope begins to diminish at the 14th dorsal, in B. 

 musculus it goes on increasing back to the 11th lumbar. The 

 measurements for this comparison are given above in Table IV. 



The spinous processes of B. borealis are very different from those 

 both of Megaptera and of B. musculus. The differences, too numer- 

 ous to be described here, will be given afterwards in a comparison of 

 B. musculus and B. borealis. The spinous processes of these three 

 whales may be characterised generally, in Megaptera as rhomboid ; 

 in B. musculus as of battledoor shape ; in B. borealis, the dorsal as 

 parallelograms, the lumbar as of hour-glass shape.] 



PART 111.— continued. 



Cervical Vertebra'. 



30. Table V., Measurements, . 107 



31. Atlas, . . . .107 



32. Axis, . . . .112 



33. The Five Posterior Cer-\acal 



Vertebme, . . .115 



T]ie Ribs. 



34. Table VI., Measurements, . 125 



35. General and Differential 



Chai'acters, . . .125 



36. Vertebral Ends of the Ribs, 131 



Sternum. 



37. Table VII., Measurements, 136 



38. Characters in comparison 



with B. muscukis, . . 136 



39. Relation of Sternum to 



First Rib, . . .138 



Chevron Bones. 



40. Characters, in comparison 



with B. musculus, . . 142 



41. Table VI 1 1., Measurements. 144 



42. E.xplanation of the Plate, . 144 



Cervical Vertebra. 



The measurements in the following Table may be compared 

 with those given in the Table of Measurements of three series 

 of the cervical vertebrse of B. musculus, in this Journal, vol. vii., 

 November 1872.^ 



1 The paper referred to, " On the Cervical Vertebra and their Articulations in 

 Fin-Whales," contains a full account of the characters of the cervical vertebrae in 

 Baljenoptera musculus and in B. rostrata, and of their articular surfaces and 

 ligaments, including the variations presented by the three complete sets of the cer- 

 vical vertebrje of B. musculus and by other specimens of atlas and axis of that 

 species. The characters in B. musculus there described are assumed here, and are 

 occasionally referred to only for comparison with those of Megaptera. It will 

 be understood that "the B. musculus" noted in the following account is the 

 50-feet-long B. musculus with which the Megaptera is compared throughout 

 this paper, unless the other specimens described in the previous papers are 

 mentioned. 



