BAL.E.Xin.E 237 



Mr. Robert Gray. In this species all the peculiarities which 



distinguish the head and mouth of the Whales from those of other 

 mammals have attained their greatest development. The head is 

 of enormous size, exceeding one-third of the whole length of the 

 creature. The cavity of the mouth is actually larger than that of 

 the body, thorax and abdomen together. The upper jaw is very 

 narrow, but greatly arched from before backwards, to increase the 

 height of the cavity and allow for the great length of the baleen 

 blades ; the rami of the mandible are widely separated posteriorly, 

 and have a still further outward sweep before they meet at 

 the symphysis in front, giving the floor of the mouth the shape 

 of an immense spoon. The baleen blades attain the number 

 of 380 or more on each side, those in the middle of the series 

 having a length of 10 or sometimes 12 feet. They are black in 

 colour, fine and highly elastic in texture, and fray out at the inner 

 edge and ends into long, delicate, soft, almost silky, but very tough, 

 hairs. The remarkable development of the mouth and the structures 

 in connection with it, which distinguishes the Eight Whale among 

 all its allies, is entirely in relation to the nature of its food. It 

 is by this apparatus that the animal is enabled to avail itself of 

 the minute but highly nutritious crustaceans and pteropods which 

 swarm in immense shoals in the seas it frequents. The large mouth 

 enables it to take in at one time a sufficient quantity of water filled 

 with these small organisms, and the length and delicate structure 

 of the baleen provide an efficient strainer or hair-sieve by which the 

 water can be drained off. If the baleen were rigid, and only as 

 long as is the aperture between the upper and lower jaws when the 

 mouth is shut, a space would be left beneath it Avhen the jaws were 

 separated, through which the water and the minute particles of food 

 would escape together. But instead of this the long, slender, 

 brushdike, elastic ends of the whalebone blades fold back when 

 the mouth is closed, the front ones passing below the hinder 

 ones in a channel lying between the tongue and the loAver jaw. 

 When the mouth is opened, their elasticity causes them to 

 straighten out like a bow unbent, so that at whatever distance 

 the jaws are separated the strainer remains in perfect action, 

 filling the whole of the interval. The mechanical perfection of 

 the arrangement is completed by the great development of the 

 lower lip, which rises stiffly above the jaw-bone and prevents the 

 long, slender, flexible ends of the baleen from being carried 

 outwards by the rush of water from the mouth, when its cavity 

 is being diminished by the closure of the jaws and raising of the 

 tongue. 



If, as appears highly probable, the " bowhead " of the Okhotsk 

 Sea and Behring Strait belongs to this species, its range is circum- 

 polar. Though found in the seas on both sides of Greenland, and 



