90 ESCHRIOHT AND REINHARDT 



fossa is, in conformity with the form of the entire cavity, far less broad than high. These bones, 

 however, project in front in a downv^ard and outward direction, so as to cover the orbital processes 

 of the frontals, and even to enclose this prolongation near its root like a half sheath, of which, 

 in the newborn animal at least, the upper part is visible from above (Plate III, fig. 1, b), though not 

 so strongly developed as in the humpbacks. Its lower part, on the contrary, is in the Green- 

 land whale still more distinctly prolonged in an outward direction, in a semitubular form 

 (Plate TV, fig. 2, b), with its concave part turned upwards, and thus it joins the orbital process 

 of the frontal in such a way that the optic nerve, in its inner part at least, is encased in a completely 

 closed bony tube. The semitubular groove formed in this way by the parietal is still further 

 strengthened by a similar, but much shorter, semitubular portion of the pterygoid (Plate IV, 

 fig. 3, a). 



Of the occipital bone it has already been stated that it is so imperfectly developed in the 

 newborn Greenland whale that its part of the primordial cranium is still cartilaginous where it meets 

 the squamous portion and the sphenoids, as well as between its own three separate ossifications, 

 namely, the basal and the two articular portions. The articular portions, both with their lateral 

 prolongations and with their condyles, are still at this period partially prominent on the lower 

 surface of the cranium, and the occipital foramen is not yet advanced entirely up to its superior 

 surface ; it is therefore the more surprising that the squamous portion of the occipital is already 

 fully as far advanced over the parietals and the frontals (see Plate III, fig. 1, 6), as in the full- 

 grown individual. 



While thus the lateral portions of the occipital are still distinctly separated by a 

 cartilaginous strip from the squamous portion, their exterior edge, which meets the temporal, 

 has only a sKght sigmoid curvature, and is quite even and uniformly smooth in its whole 

 extent. Afterwards, when all the separate bony elements of the occipitals are firmly united 

 with one another, these earlier relations are scarcely to be recognised any longer. The external 

 part of the temporal fossa has grown out in the form of a strong ridge, towards which the 

 adjoining part of the sigmoid edge on the occipital is raised. The lateral prolongation of the 

 temporal, on the other hand, has been produced very strongly in a transverse and outward direction; 

 the adjoining part of the articular portion of the occipital has followed it in this metamorphosis ; 

 the posterior surface is on a level with the same surface of the lateral prolongation of the temporal, 

 and the exterior half of that sigmoid lateral edge of the occipital forms an indented suture, running 

 in a backward and inward direction, which indicates the boundary between the respective shares 

 of the two bones in the lateral parts of the occiput. 



Instead of entering on a more detailed description of the upper surface of the occipital of the 

 Greenland whale cranium, we think we shall do better in referring our readers to the illustrations we 

 have given of it; but we cannot leave it without noticing the fact that, compared with other parts, 

 it is often found uninjured in those fragments which are usually placed before the zoologist for his 

 decision as to their species. In the first part of this memoir such a fragment of a whale, found by 

 MiddendorfF's expedition on the north coast of Siberia, was mentioned, which, judging by two 

 drawings of it, which we owe partly to Mr. Branth of the expedition, partly to the celebrated 

 leader of the expedition itself, we should hesitate in referring to the same species that is the chief 

 subject of our researches. One of these drawings we place before our readers in the annexed 

 woodcut, for a closer comparison with om* illustrations of the Greenland whale. It will be 

 found that, as the narrowness of the upper jaw is in itself sufficient to exclude any thought of its 



