— 118 — 



This vertebral-formula tallies exactly with that of a foetus of Bal. mus- 

 culus L., obtained in 1901 off Newfoundland, and referred to by True (6) 

 p. 182. It should however be borne in mind that many other vertebral-formulae 

 mentioned, all deviate more or less from the figures given here. 



Side by side with the great similarity however the vertebrae also display 

 characters proper to each separate group, though the typical features charac- 

 teristic of each group are not equally pronounced in all the representatives of 

 each of those groups. The central vertebrae of each group do indeed display 

 distinctly the characteristic features, but as we pass from one group to another 

 we find transitions. 



This regards both the different processes and the shape and size of 

 the bodies or centra. Only the atlas and the axis, the first two cervical 

 vertebrae, bear their special features. 



Vertebrae colli, fig. 11 — 19. 



The first vertebra (atlas) (fig. 11 and 12) clearly shows all the characte- 

 ristic features of this bone as occuring in the genus Balaenoptera. For the 

 shape and dimensions of this the student may conveniently be referred to fig. 1 1 

 and 12. 



It is, however, worth noting that in Flower (4) there is a description of a 

 finback-whale washed ashore on the N. W. coast of Java (Balaenoptera 

 schlegelii) whose head bears the general character of Balaenoptera sibbald'd 

 Gray. From this description to which a.o. several illustrations of cervical 

 vertebrae are added, it may be distinctly gathered that this Balaenopter repre- 

 sents quite a different species from the one to which the specimen in the 

 ßuitenzorg Museum belongs. On these grounds the points of difference from 

 Flower's description will be mentioned in the treatment of the vertebrae colli. 



In the atlas (fig. 11 and 12) the articular facets in combination with the 

 occipital condyles assume a vertical position and the neural foramen is a 

 vertical perforation of equal breadth throughout; the spinous process is some- 

 what larger and more pointed, and the transverse process situated a little 

 higher than in the case illustrated by Flower. The two anterior articular 

 sockets are very smooth in agreement with the occipital condyles resting on 

 them and extending some way behind. Both the two articular cups combined 

 and the two occipital condyles considered as one whole, are parts of a 

 spherical surface, so that the articulation in question is a ball-and-socket 



