320 



DISCOVERY REPORTS 



HAIR 



In both Blue and Fin whales hairs occur (a) at the symphysis of the mandibles, 

 (b) along each ramus of the lower jaw, (c) on the dorsal surface of the rostrum. They 

 are best developed in young whales and foetuses, for in old whales they tend to become 

 rather short and reduced in number. 



Previous descriptions of the hairs have been given by Lillie (1910) and Japha (191 1). 

 The latter gives an account of the structure and histology of the hairs in five species 

 of whalebone whales and six species of toothed whales. 



The "beard" consists, in most whales, of between twenty and forty hairs arranged 

 in two vertical rows which are often a little asymmetrical, and which tend to diverge 

 slightly. The actual length of the rows is about i ft. in medium sized whales. In 

 Fig. 52 the arrangement of the chin hairs of seven Blue whales and the hairs on the 

 rostrum of three are shown. 



Along each mandible there is normally a row of a few hairs varying in number from 

 about two to a dozen. In Fin and Sei whales two rows on each side are occasionally 

 found, but this does not seem to occur in Blue whales. 



Blue Whales 



On the rostrum also the number of hairs is very variable. It is practically impossible 

 to examine the hairs on both sides since on the flensing platform the whale lies with 

 the dorsal surface of the head resting on the ground, but usually there are between 

 ten and twenty on one side. There is usually a row along the edge of the rostrum, a 

 small group near the blowhole, and a few odd hairs in other positions. 



The hairs of the chin have been counted more systematically than those of the 



