140 A NATURALIST ON DESERT ISLANDS. 



they had either gone to form thick deposits of ooze and 

 mud ; or, like manna falling from above, had provided 

 food for another vast host of larger marine animals 

 (molluscs, crustaceans, marine worms, starfish, etc., etc.) 

 which lived on or near the bottom, on the same slopes. 



This surface population of minute creatures (or Plankton 

 as it is now called) is of immense interest. It consists 

 of a multitudinous community, of either microscopic, or 

 exceedingly frail and delicate organisms ; for the most 

 part transparent or jelly-like and possessed of colours 

 which harmonise marvellously with the tints of the water 

 in which they live. This incredible host drifts hither 

 ^nd thither at the mercy of wind and tide ; and while 

 continually preying, one upon another, its individual 

 members are as continually preyed upon, either directly 

 or indirectly, by every creature of the sea which can 

 exercise more or less volition in regard to its movements 

 and conduct generally (Nekton). 



Tempting as the subject is, it is impossible to do more 

 here than state briefly, that starting on the lowest rung 

 of the ladder of life, the creatures which make up this 

 surface-drift in the Caribbean district, range from the 

 most lowly forms of plant and animal life, like the 

 Diatoms and Foraminifera, through the various divisions 

 of invertebrate life, until they reach the pelagic molluscs. 



Upon the ample bosom of the Equatorial current, 

 myriads of fascinating life-forms, such as these, are borne 

 along, the sport of wind and stream. Along its whole 

 silent but majestic course, past the Brazilian coast, 

 through the sieve-like chain of the Lesser Antilles, and 

 over the warm surface of the Caribbean basin, this 

 equatorial current had been dropping countless myriads of 

 such like creatures, for countless generations, to strew 

 the bottom of the sea ; and as it swept over the site of what 

 would one day be Swan Island, it dropped countless others, 

 before it passed on its irresistible course through the 

 Yucatan Straits on its way to become the Gulf Stream. 

 Once arrived at the bottom, the " fleshy " parts of these 



