NATURAL HISTORY STUDIES 



surface of the sea and of the dry land ! The coldness 

 of the deep water seems to be mainly due to a flow 

 of cold bottom-water from the Southern and Antarc- 

 tic Oceans towards the equator, and in a less degree 

 to a similar flow from the sub-Arctic region. 



Deep-Sea Pycnogonid or " Sea-Spider, 1 ' Pipetta, with extra- 

 ordinary length of limb in proportion to the size of the body. 

 The males carry the eggs. (After Loman.) 



Darkness. There is very little penetration of 

 light beyond 250 fathoms, so that the world of the 

 Deep Sea is in utter darkness, save only in so far 

 as that is relieved by gleams of " phosphorescent " 



210 



