194 DR W. B. DRUMMOND ON 
the whales and other animals that feed upon them. Meduse 
and Tunicata are abundant in the warmer regions; while 
the larve of bottom-loving forms are naturally found in 
greatest abundance in the surface water near the coasts. 
A very marked contrast between the terrestrial fauna and 
the fauna of the sea must now be referred to. This is, that 
practically all the surface animals—practically all marine 
animals, I may say—lead a predatory existence, the larger 
preying upon the smaller from the top to the bottom of the 
series. The right whales devour myriads of Crustacea and 
Mollusca; the toothed whales and the seals live largely upon 
fish ; the larger fishes devour the smaller and consume also 
crustaceans, shell-fish, urchins, and star-fish ; the larval and 
post-larval fishes, as we have seen, subsist chietly upon the 
Copepods and upon free-swimming larve of other forms; the 
Infusoria not only supply food to the Copepods and smaller 
larve, but are sometimes so abundant that they may be 
found in masses in the stomachs of comparatively large 
animals, such as sardines. 
The fauna of the sea, in this respect, presents a marked 
contrast to the fauna of the land, which is so obviously 
dependent on vegetation. Yet in the sea, as on the land, it 
is given to the plant alone to feed upon inorganic material ; 
to raise the inorganic into the organic. The entire animal 
life of the sea is, and must be, dependent upon plant life. 
Yet we have said nothing hitherto about plant life. The 
existence of plant life has not been obvious. Here, then, is 
one of Nature’s secrets. Sunlight can penetrate but a slight 
way into the water, and without sunlight, plant life cannot 
flourish. The Algze and seaweeds which fringe the rocks 
around the coasts extend but a short way over the bottom. 
In the famous Sargasso Sea we find a large area crowded 
with the floating Alge, yet this covers but a trifling area of 
the ocean’s surface. Something else is required to explain 
the development and maintenance of the pelagic fauna. 
This is found in the development over the entire surface of 
the ocean of a comparatively small number of species of 
microscopic plants, for the most part Diatoms and Oscil- 
latoriz. What these lack in number of species they make. 
up for in the number of individuals produced. It has been 
ee 
