54)8 ACCOUNT OF THE AllCTIC IlEGIONS. 



and by it be conveyed back again into their proper 

 element. The fact of the olive-green coloured sea- 

 water maintaining a great similarity of position, 

 for many years together, while surface after surface 

 of ice is carried away by the current and dissipated, 

 is in support of this conjecture. Thus, by a most 

 beautiful contrivance, a large portion of the surface 

 of the globe is rendered habitable, which would 

 otherwise be a solid mass of ice ; and, by the warmth 

 of the lower stratum of the polar sea, it is rendered 

 congenial to many tribes of animals which must 

 otherwise have incumbered other regions, now af- 

 fording products useful for the subsistence of man. 



Medusa ? (Plate XVI, Fig. 3. natu- 

 ral size.) An extremely sensitive animal. When 

 touched, or indeed when the vessel in which it is 

 contained is moved, it shrinks into an irregular glo- 

 bular mass. It is divided into eight segments by 

 as many rows of finny fringes. These, though only 

 perceptible by their iridescence when in motion, 

 are capable of moving the animal through the wa- 

 ter. Its colour is greyish-white, but reddish, (pale 

 lake red), in the longitudinal cavity. Occurs in 

 the Spitzbergen Sea. 



Medusa ? (PL XVI. Fig. 5., natural 



size.) Eight segments. Sensitive. Iridescent frin- 

 ges. Single cavity. Occurs in the Spitzbergen 

 Sea. Colour similar to the former. 



