204 WHALES AND DOLPHINS 



from either side of the palate and hangs down into the cavity 

 of the mouth. Upwards of 300 plates usually make up one 

 " side ". The plates are inserted in the palate at right angles 

 to the long axis of the head, and a space of about a quarter of 

 an inch separates one plate from the next. The plate itself is 

 normally about a third of an inch thick and is roughly 

 triangular in outline. Of the three margins much the 

 shortest is that attached to the palate, and of the remaining 

 two one is smooth and the other, that on the inner side, is 

 frayed out, so that with the adjoining plates it combines to 

 make an efficient sieve for straining water containing food 

 organisms. 



Apart from the possession of baleen, their enormous size is a 

 feature which distinguishes the Whalebone Whales from other 

 Cetacea : only the Sperm among the Toothed Whales can 

 compare with them in this respect. Another distinctive 

 feature is the paired blowhole, formed by the nostrils opening 

 to the exterior by two distinct longitudinal slits. The group 

 includes the great Blue Whale, which may grow to a length 

 of nearly 100 feet, and even Neobalaena, the pigmy of this 

 sub-order, may be up to 20 feet in length. All the remaining 

 species are at least 30 feet long when fully grown. 



RIGHT WHALES. 



Family Bal^enidjE. 



The Right Whales receive their popular name from the 

 fact that at the time when they were hunted to the exclusion 

 of all other kinds they were the " right " whales to be pursued. 

 They are distinguished from the next family by the absence 

 of grooving or furrows externally on the throat, by the 

 absence of a dorsal fin (except in the little Neobcdaena), by 

 the presence of very long, narrow, flexible whalebone blades, 

 by the great development of the lower lips, which project 

 upwards on either side and have the strongly arched narrowed 

 upper jaws lying between them when the mouth is closed. A 

 variety of internal characteristics also distinguishes this 

 family, but the only one that needs to be mentioned here is 

 that the 7 neck vertebrae are fused into a single unit. 



