THE ORDER CETACEA. 17 



The head of the balcena mysticetus constitutes rather 

 more than one-third of the entire length of the whole 

 body, as the foregoing diagram exemplifies ; but it fre- 

 quently exceeds these dimensions, and approaches to 

 one-half, and is somewhat of a triangular shape : the 

 inferior half of the arched outline, formed by the lower 

 jaw-bones, is flat, and measures from sixteen to twenty- 

 five feet in length, and about ten or twelve feet in 

 breadth. The lips extend from fifteen to twenty feet in 

 length, and about five or six in Jieight ; forming the 

 cavity of the mouth, they are of course attached to the 

 lower jaw, rising from the jaw-bones at an angle of 

 about eighty degrees, bearing the resemblance, when 

 viewed anteriorly, of the letter U inverted. The upper 

 jaw, including what the sailors denominate the crown- 

 bone or skull, is bent down at the extremity, so as to 

 completely shut the anterior and inside portions of the 

 cavity of the mouth, being enveloped by the lips in a 

 squamous manner at the sides. 



The eyes are about the dimensions of a moderately- 

 sized orange, being scarcely in diameter the hundredth 

 and ninety-second part of the total length of the body, 

 being half as large again as the visual organ of the ox ; 

 and the crystalline lens, when dried, is not much larger 

 than a pea.* They are placed towards the posterior 

 part of the head, it being the most convenient situation 

 for enabling them to see both before and behind, as also 

 to allow them to see above their head, when below the 

 surface, where their food is principally found. The eyes 



and the whalers ; Bal&na Major Bippinis, Sibbald. " Phainolog. Nov. ;" 

 Common Whale, Pennant's " Brit. Zool." vol. iii. ; Great Mysticete, 

 Shaw's " Zool." vol. ii. p. 2. 



* Vide " Ency. Londin." vol. ii. p. 637 ; also Cuvier, " Regue 

 Animal," vol. iv. 



C 



