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Show 46 ON THE BONNET OE THE SOUTHERN RIGHT WHALE. [Eeb. 5, also Nathusius, Arch. f. Anat. u. Phys., Leipzig, 1869, pp. 76-80), and in baleen or " whalebone," in which a strongly marked, superficial, stratified layer is present in addition, especially in the basal parts (fig. 6 : see also Milne-Edwards, Lecons sur la Physiol. vi., Paris, 1860, p. 120). The stiff hairs on the tail of the Elephant are described by Naunyn ' as intermediate in character between simple hairs and Ehinoceros horn. Even the horns of Oxen and Goats show, in their deeper, most recently formed layers, a closely analogous structure. This becomes lost in the outer layers in consequence of the compression which the fibres undergo-they first become elliptical or crescentic in section, and finally so flattened that the outer layers exhibit a marked stratification. The skin of Whales is peculiar in structure 2. Not only is it practically hairless in the adult condition, but it is devoid of glands, and cutaneous nerves are scarce. The stratum corneum is very thin, but the rete malpighii is strongly developed, and is traversed by numerous very long, vascular papilla?. The corium, as a layer, is in most cases almost completely wanting. Elongated, finger-like papilla? of this kind are, be it observed, not confined to Whales. They occur in most cases where the skin attains an unusual thickness, and they serve the purpose, as Leydig 3 pointed out, of supplying nourishment to a thickened epidermis, since the epidermis, being but slightly pervious, cannot absorb the nourishing plasma through more than a limited thickness of its substance. Long papilla? were remarked by Steller in the skin of Rhytina; they occur in the skin of the Hippopotamus, particularly in the region of the upper lip *, in the hairless skin on the muzzle of the Ox5, in the snout of the Pig, and on the point of the proboscis of the ElephantG. I have not had an opportunity of examining sections of the skin of the Whale, but the published descriptions go to show that the structure of the " bonnet" under consideration does not differ in essential features from that of the stratum corneum of the normal skin; for this exhibits just the same disposition of the cornified cells. Heusinger, for instance, in describing the skin of Balcena mysticetus, writes :-" Die Lederhaut ist ausserst diinn oder fehlt ganz ; dagegen findet sich eine mehr als zolldicke Schicht, die aus parallelen, dicht mit einander verklebten und verwachsenen Fasern besteht; zu unterst, w o sie auf dem Eette standen, sind diese Fasern a m dicksten, nach oben werden sie diinn und sind schwer 1 Arch f. Anat. u. Phys. 1861, p. 670. 2 Leydig, F., " Ueber die ausseren Bedeckungen der Siiugethiere," Arch f Anat. u. Phys. 1859. Kiikenthal, W., " Die Haut der Cetaceen," Denkschr. d. med.-nat. Gesell., iii., Jena, 1889. 3 L. c. p. 701. 4 Leydig, I. c.; and Weber, M., ' Studien iiber Saugethiere,' Jena, 1886. 5 Nathusius, W., " Ueber die Marksubstanz verschiedener Horngebilde," Arch. f. Anat. u. Phys., Leipzig, 1869, pi. iii. fig. 11. 6 Smith, F., "Histology of the Skin of the Elephant," Journ. Anat. & Phvs xxiv. 1890. J ' |