BBIEF SKETCH OF THE TOOTHED WHALES. 87 



and usually termed " blubber," the main cause of the relentless 

 persecution which these animals suffer at the hands of man. 

 This fatty tissue attains great depth — for instance, on the 

 snout of the Pilot-Whale, and in the same region of the 

 Cachalot, where the soft, yellow, and oily mass ("junk") based 

 on the upper jaw weighs between two and three tons. Besides 

 this, however, and resting on it, is a large area, to which the 

 term ** case " is applied by the whalers, abutting on the nasal 

 canal, the whole of which is filled with an intricate web of 

 cellular tissue, containing in the interstices a clear oily fluid 

 (chiefly spermaceti). Twelve barrels, or about three hundred 

 and seventy gallons, of this material have been collected from 

 the "case" of a single example. The great accumulation of 

 these relatively light substances in the huge head of this species 

 is, in the opinion of some observers, a provision for rendering 

 the region buoyant.* 



The dorsal humps and dorsal fins seen in many of the 

 whales of this group {i. e. the Toothed Whales) have a large 

 quantity of the same fatty tissue or blubber. They are simple 

 integumentary folds with tough connective tissue and fat, as in 

 the hump of the camel (Dr. Murie). It is interesting that 

 these fins begin to develop in the young only after the forma- 

 tion of the flukes, showing perhaps that they have been acquired 

 more recently. 



As might be anticipated in animals so powerful and so active 

 as the Cetaceans, the muscular system, which lies beneath the 

 former tissues, is highly developed. An examination of the 

 plates in the elaborate paper of an old friend. Dr. Murie, t 

 shows that several powerful sheets act on the flippers, while a 

 still more remarkable series of muscles give great power to the 

 flukes of the tail. The more complex arrangements of this 

 system need not be dwelt on, but a glance at these anatomical 

 figures shows that structure in this respect conforms to function, 

 and that the swift propulsion of the huge body through the 

 water, the balancing and sounding actions of the flippers, and 

 the sculling and balancing movements of the tail, so admirably 

 told by a late colleague. Prof. Pettigrew, and which in ordinary 



* F. D. Bennett, surgeon, ' A Whaling Voyage round the Globe,' 1840, 

 t Trans. Zool. See. vol. viii, p. 238, pis. 36 and 37. 



