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Show 1901.] BONNET OF THE SOUTHERN RIGHT WHALE. 45 It is an interesting fact that the "bonnet" appears to be confined to the Southern Eight Whale. Gray has expressed his inability to find mention of the structure in any account of the Greenland Whale; and the experienced whaling captain Mr. Eohert Kinnes of Dundee writes, in a letter dated Oct. 4, 1900. that " the Greenland Whale has no excrescence on its nose." W h a t is still further of interest is the fact that in the AVhale figured by Gray in Dieffenbach's ' Travels in N e w Zealand,' vol. ii., as Balcena antipodarum, there is a prominence on the front of the lower jaw as well as on the front of the upper one. The specimens are black in colour, and very irregular in shape. T w o views of the larger specimen are uow exhibited (see figs. 1 and 2, Plate VI.). The under surface is comparatively smooth, and the formative area is rather narrower than the total width of the structure. To the naked eye the mass appears to be made up of a number of thin layers of horny matter, for in the dried condition the edges seem disposed to fray out in lamina?. But by a study of microscopic preparations the structure is seen to be one of closely packed fibres or rods, disposed at right-angles to the broader surface of the mass. Each constituent is rod-like for the greater part of its length, but is slightly hollow towards the cutaneous surface ; and in the cavity there doubtless resided a soft and vascular papilla, covered with prismatic epithelial cells, to the proliferating activity of which the increase in the bulk of the " bonnet" is due. Sections taken at right angles to the fibres (Plate VI. fig. 3) fail to show any sharply defined outlines between these constituents, the main indications of their structure being the dark air-spaces arranged in concentric series. Very little can be made out by the use of sections taken at right angles to the cutaneous surface, for, probably owing to contraction in drying, the rods are bent and twisted in all directions, and it is not possible to trace any individual one for more than a fractional part of its total length. Beddard 1 has called attention to the resemblance which this form of structure bears to that of the nasal horn of the Ehinoceros, which has always been regarded as consisting of agglutinated coarse horny fibres, differing from true hairs in the fact that their papilla? are not lodged in depressions, but exist as eminences on the surface of the skin. The constituent rods or fibres of the Ehinoceros horn, however, are sharply defined by intermediate agglutinating material of darker appearance (Plate VI. fig. 4 : see also Daubenton, Hist. Nat. de Buffon, ed. 8vo, xxiv. p. 269, pi. 318. figs. 3-7), and of a less resistant nature than the fibres themselves, for the latter tend to fray out on the basal parts of the horn. The formation of horny growths of considerable thickness by the activity of closely-set papillae, giving rise to coarse horny fibres or hairs connate from the first, is, however, by no means uncommon among Mammals. It occurs in the hoof of the Horse (fig. 5: see 1 ' Book of Whales,' 1900, p. 136. |