116 THE WHALK. 



other cetacea, however, this is not always the case; 

 some of the dolphins, in particular, having been 

 heard to emit a shrill sound, which in the beluga 

 may be heard before the animal arises to the surface 

 of the water.* 



The external blowholes or spiracles, were, in the 

 sucking whale, four inches in length; in the full 

 grown animal, they form two curved slits, above 

 ten inches long. In passing downward through the 

 blubber, the blowholes, which at the surface are 

 nearly longitudinal, as in the annexed figure, a, a, 



» Posterior. 



Anterior. 



twist iuto a semicircular and transverse position, 

 in the form of the dotted line b, b, then penetrating 

 the skull, they proceed backward and downward in 

 two conical parallel canals, until they open near 

 the back of the under part of the skull, where they 

 inosculate and form a single membranous sac, with- 

 in a few inches of the epiglottis. The first impres- 

 sion of each blowhole on the upper part of the skull, 

 is marked as in the following cut, (representing the 

 upper surface of the anterior part of the whale's 

 skull, the skin and fat being removed,) by an ob- 

 long cavity, b, b, 



* Captain Parry's Voyage for the discovery of a North 

 West passage, p, 35. 



