296 



\V H A L E S 



Epidermis ^ivi-hw^i^^^ 

 Dermis 



Loose connective 

 tissue 



Fascia == 



Muscles > 



Figure ijo. Cross-section 

 through tlie epidermis and 

 blubber of a Fin Whale. 

 {Slijper, ig34.) 



Channel swimmers invariably cover their skins with a thick coat of 

 grease, and whales have a natural thick layer of blubber. We shall now 

 look at this insulating layer in greater detail. 



The skin of all mammals, Cetaceans included, consists of an outer 

 epidermis, an inner dermis or corium, and of subcutaneous connective 

 tissue (Fig. 1 70) . The Cetacean epidermis is very thin ; in big whales it is 

 made up of a 5-7 mm. thick inner black or white layer of living cells, and 

 an outer cornified layer which is less than i mm. thick. (In Chapter 2 we 

 saw that the Cetacean skin is completely devoid of sweat glands and 

 sebaceous glands) . The dermis is a thin layer of tough connective tissue 

 immediately under the epidermis, and contains no fat. In porpoises it 

 is only o -34 mm. thick, and this is the reason why their skins (and the 

 skins of most whales and dolphins as well) cannot be used for leather. 

 The Narwhal, the Beluga, and some River Dolphins form the exceptions, 

 and their skins are, in fact, tanned in some countries. 



In the big whales, the only skin suitable for processing is that covering 

 the penis, and though it is of no industrial value, whalers sometimes turn it 

 into useful domestic articles. The epidermis is naturally in close contact 

 with the dermis, since water friction would otherwise tend to pull them 



