482 SCOTT'S LAST EXPEDITION 
the Polar regions, they would not exploit warm seas such 
as that off the north of New Zealand with a ' trying out ' 
plant suitable for South Georgia or the South Shetlands 
and so lose large sums of money. 
Fifteen rich hauls with trawl and dredge in depths 
varying from 40 to 300 fathoms enabled a large collection 
of the benthos to be made. A striking feature of the 
marine fauna of the Antarctic is the extraordinary wealth 
of individuals, while the variety of forms does not appear to 
be very great. Also the large size to which some species 
attain as compared with their relatives in warmer seas is 
very marked. 
This is, however, not the case with animals which 
require carbonate of lime, for the secretion of limy 
skeletons by members of the benthos seems to be at a 
minimum in the cold Antarctic waters. The shells of 
molluscs are small and fragile. Some sea-snails have no 
lime in their shells at all. 
It requires the warm tropical seas for animals with 
calcareous skeletons to reach their vigorous growth. 
Many of the bottom animals crawl over the sea floor 
and pass the nutritious mud through their digestive organs 
after the manner of earth worms ; others take up a 
stationary vertical position, and by means of tentacles 
waft the falling diatoms into their mouths before they 
have time to reach the bottom. 
Almost every trawl brought up quantities of large 
siliceous sponges covered with glassy spicules. 
Good collections of sea-anemones, worms, urchins, 
starfishes, Crustacea, sea-spiders, molluscs, and fishes were 
