86 THE ZOOLOGIST. 



In external form the Toothed Whales vary, from the massive 

 club-shape of the Spermaceti Whale, the head of which resembles 

 an enormous battering-ram, to the more elegant curves of the 

 active Dolphins. Some (as the Killer) have, and others (as the 

 White Whale and Neomeris) do not have, dorsal fins, and the 

 flippers are either short and broad, as in the Spermaceti and 

 Susu (Platanista) , or elongated, as in the Pilot- Whale. They 

 vary in external coloration, from the deep black of the Pilot-Whale 

 to the yellowish white of the Beluga, and the bluish colour of 

 Orcella fluviatilis of the Irrawaddy, some being variegated with 

 black and white, as the Killer and several Dolphins, or speckled, 

 as in the Narwhal. Moreover, in such as Mesoplodon, a pair 

 of gular grooves are present. 



In the structure of the skin they agree with the general 

 type already mentioned, viz. in having an epidermis of variable 

 thickness, the surface being formed of the corneous layer which 

 usually shows flattened cells, while the Malpighian layer beneath 

 presents polygonal nucleated cells with interstitial fibres, and 

 contains the pigment. Chemically, the skin shows keratin, and 

 in certain forms, as the White Whale, is manufactured into ex- 

 cellent leather, and there is no reason why the skins of others 

 should not be similarly utilized, especially when it is remem- 

 bered that the skin of the Spotted Wolf-fish is made into 

 excellent leather in Norway. In connection with the layers 

 just mentioned, it is an interesting fact that the young (year- 

 ling) White Whale is of a leaden or bluish black hue, from the 

 greater development of pigment at the inner border of the 

 Malpighian layer, but as it grows older it becomes mottled, and 

 finally assumes the soft cream-like tint or yellowish white of 

 the adult, and the nearly pure white of the old animals. This 

 perhaps indicates that the white is an acquired character. The 

 pigmented layer in the skin of the Cachalot is alkaline from free 

 soda, a great convenience to the whaler by enabling him to 

 cleanse the ship and his clothes from the oil with which the 

 alkali readily combines. 



Beneath the Malpighian layer of the skin is a thin mem- 

 brane, e.g. in such as Beluga, which probably represents the 

 true skin (corium). Then come the connective tissue and fat, 

 varying from one to several inches, 4 to 8 to 14 in. in Cachalot, 



