OSTEOLOGY OF THE PIGMY WHALE. 101 



does not seriously interfere with the understanding of the proportions of the different 

 regions, while it does not at all mask the form of the various parts of the skeleton. 

 The proportions of the length of the skull to that of the entire skeleton including the 

 skull are as 1 : SJ. It will be noticed therefore that the proportions are not those 

 of either of the whales of the genus Balmna. The proportions, in fact, are roughly 

 those of any species of the genus Balcenoptera. The proportion of the head to the 

 trunk has formed in the diagnosis of many naturalists an important feature in the 

 distinguishing of the families Balsnidge and Balsenopteridee, or of the genera Balmna 

 and Balmno'ptera, according to the views taken of the systematic arrangement of 

 the Mystacoceti. So far Neobalmna is in no sense intermediate ; it distinctly resembles 

 the Rorquals. 



But the general aspect of the skull is on the whole suggestive of that of Balcena. 

 This likeness is of course emphasized by the long whalebone, which extends in the 

 dried skull to a point considerably below the lower margin of the mandible, when that 

 bone is approximated to the upper jaw. The skull as a whole is arched and the 

 rostral part is narrow ; this latter feature is well exhibited in the figure (PL VIII. fig. 1) 

 which illustrates the skull viewed from above. If this aspect of the skull oi Neolalcena 

 be compared with the corresponding aspect of the skulls of Balceiia and Balcenoptera, 

 the closer resemblance of Neohalcena to the former genus Avill be apparent. For in 

 the Rorquals the rostrum is much broader than in Balcena. The length of the 

 rostrum also as compared with that of the rest of the skull is a feature in which 

 Neohalcena suggests a true Balcena rather than a Rorqual. The rostral portion just 

 about equals in length the back part of the skull. It is not, however, to all appearance 

 quite so long proportionally as it is in the Right Whales ; but the difference is in 

 reality due to the narrowness of the frontal bones in Balmna, a feature which seems 

 to be if anything less marked in Balcena australis than in its Greenland congener, 

 B. mysticetus. It is interesting to note that Neohalcena is nearer to what we must 

 probably look upon as the less specialized type of Right Whale ; less specialized 

 because of its wider range, variability, less arched skull, &c. It is also permissible to 

 point out that the proportions of these different regions of the skull and the degree 

 to which the bones form an arch anteriorly, are more like those of a foetus of Balcena 

 mysticetus figured by MM. van Beneden and Gervais ^ than the adult of either of the 

 two Right Whales. It may be further observed that in the young of B. mysticetus 

 the head is not so enormously large in proportion to the trunk as it is in the adult 

 of that whale. 



Coming to the details of the skull-structure in Neohalcena, we find on the whole a 

 greater likeness to Balcena, but that in certain features the characters of the Rorqual 

 appear. 



^ Osteograpliie des Cetaces, pi. i. figs. 7, 8. 



