OSTEOLOGY OF THE PIGMY WHALE. 105 



the great length of the roofing portion of the occipital bones is a very distinctive 

 feature of the whale Neohalcena as compared with its immediate allies. 



The sqitamosal (PL VIII. fig. 1, PI. IX. fig. 1, Sq.) is rather characteristic in its 

 form in this whale. The lower border of the bone projects down behind the glenoid 

 cavity considerably further than it does in front. In this region, indeed, it hardly 

 overshadows the condyle of the lower jaw, there being from before backwards a gradual 

 descent in the margin of the bone. There is, moreover, a much shorter part of the 

 lower margin of the squamosal lying in front of the condyle of the lower jaw than 

 there is behind it. On the whole the genus Balmna is most like Neohalcena in this 

 particular; in Megaptera and in the Rorquals the bone is much wider across the 

 glenoid border, and the half of the border which lies in front of the glenoid cavity is 

 proportionately much longer. This great forwardly directed process of the squamosal 

 is but feebly developed in Neohalmna. 



Viewed from above, the disposition of the squamosal differs in the three types of 

 Whalebone Whales almost equally, and Neohalmia is not any more like Baloena than 

 it is like Balcenopf era. As already mentioned, the occipital projects back for someway 

 behind a line passing through the two occipital condyles, and the backward projection 

 of the squamosal is almost exactly coextensive with the hinder parts of the exoccipitals. 

 This is to a certain degree paralleled in Bahenoptera, where the two bones end 

 posteriorly at about the same level ; but in that genus the projection of the two 

 beyond a line drawn at right angles through the occipital condyles is very much less 

 than in Neobakena. On the other hand, in Balcena the squamosal projects back with 

 an extension which is quite as fully marked as in Neohalcena, but the exoccipitals do 

 not accompany this backward projection of the squamosal. This statement is at 

 variance with the numerous figures of the skull of Balcena seen from above, such as 

 those of Gray in the ' Catalogue of Seals and Whales,' or the figures of MM. van 

 Beneden and Gervais ; but all those figures represent the skull viewed in such a fashion 

 that the occipital condyles are entirely or nearly entirely exposed. My own comparison 

 represents the skulls of these three whales viewed more directly from above without a 

 complete exposure of the condyles. 



In the arrangement of ih.e pterygoids and the palatines, Neohalmna is much like the 

 Right Whale ; in Balcenoptera the pterygoids have a marked backwardly directed 

 spur ; of this there are only traces in Neohalcena. 



The lower jaw of Neohalcena is remarkable on account of its great depth. Its 

 curvature is sigmoid, and the symphysis is preceded by a decided dip downwards in 

 the direction of each mandible. The coronoid process is quite feebly marked, but is 

 still perfectly recognizable (as is to be seen in PL IX. fig. 1, C). When viewed from 

 above (PL VIII. fig. 1) the spoon-shaped outline of the interspace between the two 

 rami of the mandible is seen to be but feebly represented. 



q2 



