80 ESCHRICHT AND REINHARDT 



two branches of the lower jaw are widely separated from each other, and the space between these 

 three, comparatively speaking, small bones, is in that way rendered so large, that the bones them- 

 selves almost dwindle into mere outlines of it. 



In the description of the exterior it has already been mentioned, how the large space 

 between the narrow upper jaw, and the rami of the lower jaw is covered on either side by the 

 underlip. Even in the newborn individual this underlip deserved to be called extraordinarily 

 high (Plate I, fig. 1) ; how large its dimensions must be in the full-grown whale, we may 

 imagine pretty accurately by considering, that it covers the whalebone-blades, sometimes even 

 upwards of twelve or thirteen feet long, with the exception of their lowest extremities, which 

 are situated between the rami of the lower jaw and the tongue ; but in the skeleton we have a 

 perfectly exact, though not direct, picture of the extraordinary dimensions of the underlip, shown 

 by this great distance between the upper and the lower jaw. 



If we consider the two underlips as the side walls of the cavity of the mouth, part of this 

 cavity isj of course, occupied by the whalebone ; but the laminæ are here so narrow in proportion 

 to their length, and besides curved in such a way, and placed one overlapping another, that they 

 may to a certain degree themselves properly be considered as part of the side walls. An 

 exceedingly large space is, at all events, still left between the two sets of whalebone. As long as 

 the mouth is kept shut, this space is occupied by the tongue, which may certainly be called the 

 most colossal of all the organs of the Greenland whale; but when the mouth is opened, and the 

 tongue drawn back, it is filled with the water of the sea containing large quantities of Crustacea 

 and free swimming moUusca, streaming into the mouth in front, and then leaving it through 

 the whalebone grating, when the mouth is shut again, while all these small animals are left on 

 the hairy covering of the inner side of the baleen. 



In the rorquals, the cavity of the mouth is comparatively small in conformity with the 

 much smaller quantity of water which is admitted into it with the food. As regards the 

 height this may be observed even in the skeleton, where the surface of the palate can scarcely 

 be said to be arched at all from before backwards ; as to breadth, on the other hand, it can only 

 be understood by imagining the surface of the palate covered with its whalebone. The surface 

 is, not only relatively to the length of the head, but also absolutely speaking, broader than that of 

 the Greenland whale, and the lateral rami of the lower jaw are curved even more strongly in an 

 outward direction from each other, but the cavity of the mouth very broad in itself, is in reality 

 very much reduced by the whalebone. This is partly caused by the whalebone itself being, 

 comparatively speaking, very broad, the laminæ of the humpback, for instance, only two or three feet 

 long, being scarcely narrower than the very largest blades from the Greenland whale, but especially, 

 by their being all curved transversely, so as to have their smooth outer edge concave, and the 

 hairy inner side convex. In the baleen of the right-whales no such curve is found to reduce 

 the space of the cavity of the mouth, except in the most posterior blades. We have already 

 stated of the laminæ of the Greenland whale, that the greater part of them are, on the contrary, 

 curved in an opposite direction, by w^hich means the cavity of the mouth is rendered wider. 

 .Judging only by the outline of the cranium, we might suppose, that the cavity of the mouth of 

 the rorquals, at least quite in its most posterior part, was broader than that of the Greenland 

 whale, as the lateral parts of the cranium are much more extended in an outward direction, 

 but in its natural connection with the lower jaw, it will be seen directly that its extension in 

 width adds nothing to the width of the mouth, as the branches of the lower jaw, bending where 



