SCANDINAVIAN CETACEA. 



283 



The sternum (fig. 4) is very characteristic. It is concave in front, where it has on each 

 side a large wing-like process, and terminates in a long round process or point. There is on each 

 side, behind the wing-like process, a rough protube- 

 rance, to which probably was united the cartilage of 

 the 1st pair of ribs. This sternum has some similarity 

 with certain forms of the same bone in B. musculus. 



The ribs are thick and large, almost like those of 

 Balæna mysticetus ; they are generally thin and com- 

 pressed towards the lower end. There are, as previously 

 stated, at least 15 pairs, and probably not more. The 

 1st pair are unknown. All those that have been found 

 taper at the lower end, while, on the contrary, the 

 1st pair in all Fin whales and in B. mysticetus are 

 wider at the lower end. Those of the supposed 2nd 

 pair resemble very closely the same pair of the skeleton 

 of B. musculus in Bergen ; they have a rudiment of a 

 collum, which is most developed on the left one, and are, 

 in comparison with their length, somewhat wider than the 



succeeding ones, and more curved. The 4th — 6th pairs have a strongly developed tuberculum, 

 which is 2" high on the first two pairs.^ The 4th — 5th pairs have a longer collum, which, on the 

 former, is 7" long, and has on both pairs a conspicuous capitulum at the point, which, however, 

 does not reach to the corpus of the corresponding vertebra, when the tuberculum is united to 

 the lower concave part of the end of the processus transversus. There is hardly any capitulum 

 on the 6th pair, which are the longest of all. The hinder pairs have the upper end flattened. 

 The 10th — 15th pairs decrease gradually in length and in thickness, the latter being only 4' 2^" 

 long, very narrow, with sharp edges towards the lower point, with an undulating curve, and 

 with the upper end somewhat button-shaped. 



The scapula (fig. 5), like the lower jawbones, 

 is quite characteristic of the species. It seems, F'g-S- 



in its form, to be between that of Balænoptera 

 and that of Balæna. It is narrower than that of 

 the other species of the former genus, but wider 

 than that of those of the latter. Its width at 

 the upper part exceeds the length by between \ 

 and i. Compared with the scapula of Balcsna, 

 it is much wider. The acromion is large (9" long), 

 but the processus coracoideus is rather short (5^" 

 long). These processes are not far separate, and 

 the acromion is directed somewhat upwards ; but 

 the angle that it forms with the upper part of the 

 fore edge of the scapula is not very acute. 



The humerus resembles the same bone in the other Balænopteræ by its caput being subter- 

 niinal and very little turned inwards. 



' I have observed a tuberculum, as strongly developed, only in Balæna mysticetus. 



