104 MK. F. E. BEDDAUD ON THE • 



Tn tli(> first i)lacL>, tin' premaxilhc of Baloena embrace the whole length of the nasal 

 bones, and even extend beyond them ; in the second place, they appear to be in contact 

 anteriorly for rather a greater extent tlian is the case witli Neohahena. These bones 

 are altogether more prominent upon a dorsal view of the skull than in Neohaloena. In 

 the Rorquals the premaxillse are still more different from those of Neohalcena. They 

 only reach the anterior half of the nasal bones, the maxillae, as already stated, arti- 

 culating with the latter bones. This is not, however, always the case, for van Benedeu 

 and Gervais fio-ure a dorsal view of the skull oi BalcBnoptera sibbaldi in which the 

 premaxillaj not only reach the entire length of the nasals, thus cutting them off from 

 the prem axilla;, but extend considerably beyond them. On the other hand, in a skull 

 of -5. rostrata the premaxillse stop short of the nasals. These differences, possibly due 

 to the state of ossification of the skulls in question, may therefore be regarded as of 

 less importance than the fact of the great backward extension of the maxillae, which 

 occurs in all skulls of Balmnoptera. 



The occipital bone of Neobcdwna is remarkable for its great length, which gives to 

 the back part of the skull a much greater extent proportionately than in other Whale- 

 bone Whales. This is clearly seen in the drawing which shows the skull when 

 viewed from the side (PI. IX. fig. 1) more clearly than in that (PI. VIII. fig. 1) which 

 exhibits the skull from above. The exoccipital regions on either side of the condyles 

 project much further back along the squamosals than in any Balcena or Balcenoptera. 

 Superiorly the occipital is naturally wider behind than in front ; it is ridged along the 

 middle line and terminates anteriorly in a square face of articulation with the frontals. 

 The diameter gradually diminishes from the back part of the skull to the anterior end 

 of the bone. The length of the bone is greater than the width of any part which 

 appears on the dorsal surface of the skull, as is seen in the figure referred to (PI. VIII. 

 fig. 1). 



The posterior contour of the occipital is different from that of either Balcena or 

 Balcenoptera. The lateral parts of the bone jut out considerably beyond the level of 

 the condyles, while in Bala^na the posterior transverse line of the skull is nearly 

 straight, less so, however, in older than in younger specimens. In Balcenoptera we 

 find the same relative straightness of the posterior face of the skull. The differences 

 appeared to me, from a comparison of actual skulls, to be rather greater than is 

 depicted in the figures illustrating the ' Osteographie des Cetaces.' Viewed from 

 above the form of the occipital is not uncharacteristic. For in Balwna this part of the 

 bone is as broad as it is long, or nearly so, and of a more rounded form than in 

 Neohalcena. In Balcenoptera the bone is also comparatively short and wide, and, 

 moreover, it does not nearly reach to the anterior end of the orbital plates of the 

 frontal. In Neohalcena it very nearly does so, and in this feature the skull of 

 Neobaltena is much more distinctly to be compared with that of Bala^na. Indeed 



