100 Mil. l'\ E. BEDDAlli) O.N THK 



whale which dives more persistently and for greater periods of time than any of its 

 allies, the large number of ribs and the fact tliat so many of them are so imperfectly 

 attached to the vertebral column would be intelligible. But we have no knowledge of 

 tlie habits of this whale which could allow of any such a theory. 



The Sternum. 



The great care which must be exercised in using the sternum as a character of 

 generic or specific importance in whales, is illustrated by that of the present species. 

 Sir James Hector correctly figures the sternum of the individual studied by himself, 

 and well describes it as " bearing a striking resemblance to a scutcheon." It has in 

 fact precisely this form in the smaller and immature skeleton of Neobalcena in the 

 British Museum. The anterior border projects in the middle line, and again on both 

 sides, while the margins are rounded and converge slightly posteriorly. On the other 

 hand, as will be seen from the drawing which I exhibit here (PI. IX. fig. 2), the 

 sternum of the larger and more mature skeleton is quite different. It has, as will be 

 seen, somewhat the form of a Maltese cross. The anterior border, the posterior 

 border, and both sides are excavated at points exactly, or very nearly exactly, opposite 

 to each other, so that on the whole a cross-like form is produced. The anterior 

 excavation is the deepest of the four. The two lateral excavations are rather more 

 pronounced than that of the posterior border. In the figure to which I liave just 

 referred, the sternum is viewed a little in profile owing to the position of the 

 skeleton and the impossibility of getting a direct dorsal view. But no confusion can 

 arise in consequence as to the shape of the bone and the proportions of its different 

 parts. Now it is curious that the sternum which appears to be the more unfinished, 

 i. e. the least ossified, is that of the demonstrably older individual. The filling in of 

 the anterior excavation with bone and its projection forward would certainly appear at 

 first sight to be a mark of age. It may still be the case that the specimens are really 

 of different species. But other considerations forbid this assumption in my opinion. 

 The variability of the form of the sternum is only another illustration of the fact that 

 degenerating organs tend to vary considerably. But the variations of form of this 

 organ seem to be greater in Neohalcena than in any other ^^^halebone Whale. 



The Skull. 



As will be seen from an inspection of the large drawing (PI. VII.), which is illustrative 

 of the entire skeleton of Neobalcena, the skull is not large in proportion to the rest of 

 the skeleton. That drawing, it should be explained, is not exactly parallel to the 

 horizon. The position of the skeleton in the Whale Gallery at the Museum rendered it 

 impossible to obtain an accurate horizontal sketch. The amount of obliquity, however, 



