ORDER CETACEA. 487 



dom of the arrangements of nature, and the exquisite exacti- 

 tude of her adaptations. 



The Whale has an organ of vision admirably conformed 

 to the aqueous and saline element, to the thick and humid 

 atmosphere through which it is destined to see objects. It 

 can, moreover, as we have already observed, intercept any 

 inconvenient quantity of light, by interposing between it 

 and the eyes a veil, which it can render more or less opake 

 according to the degree of depth to which it chooses to sink 

 below the surface of the waters. It can exercise this organ 

 as it pleases. By elevating its head above the water, it can 

 place it so as to extend its view over an immense plain 

 formed by the surface of the tranquil sea, and the only limits 

 to its power of discernment, are the smallness of objects or 

 the curvature of the earth. 



The eye of the Whale is in general conformed like that of 

 fishes. Its crystalline is tolerably convex before and spherical 

 behind. Its general form is maintained in a great measure, 

 by the envelope called the sclerotica, which instead of be- 

 ing simply attached to the cornea by a cellulosity, most 

 usually penetrates into the corneous substance, by long and 

 fine ligaments. In the choroid are observable the apertures 

 of the vessels, and also the internal membrane, called 

 ruyschian : we can even count the radiating fibres which are 

 disposed circularly, and surround the crystalline. 



The pupil of the eye is susceptible of contraction by 

 means of the dilatation of the iris, and of becoming a trans- 

 versal elongated aperture. It is moved by four straight 

 muscles, and by another called the suspensor muscle, which 

 is divided into four ; there are, moreover, two oblique 

 muscles superior and inferior. 



The Balsense in common with the majority of aquatic 

 animals, have no lachrymal glands. Their place is supplied 

 by two sorts of lacunae, situated under the upper lid, from 

 which distils a thick and mucilaginous humour. 



