386 ANN"UAL EEPOKT SMITHSOI^IAN IKSTITUTION-, 1916. 



portion of the year and is available only in those shallower waters 

 in which it is fitted to flourish. Out upon the wide ocean, compris- 

 ing roughly three-fourths of the surface of the globe, it is the diatom 

 which is the plant par excellence as the supplier of animal food. It 

 also shares this serAdce with the other plants above mentioned in 

 the shallow^er waters of the coast. 



The full value of the diatoms in this particular is only recently 

 being appreciated. It seems strange that the study of this im- 

 portant point has been so long deferred; as strange as if the stock 

 raiser should have persistently neglected the study of those forage 

 crops upon which the welfare of his stock depends. The enormous 

 value of the fisheries to the world, to the inhabitants of all lands, is 

 the measure of the importance of the study of these minute organisms, 

 because of their intimate relationship to the problem of fish food. 

 When the diatom flora of our coasts and of the high seas is suffi- 

 ciently investigated we shall be in a position to understand better such 

 problems as the migration of fishes and the prevalence of certain 

 kinds in certain waters ; and it is not improbable that means will be 

 devised for augmenting the fish food suppl}^ through the diatoms, 

 just as the science of agrostology works toward the betterment of the 

 cattle raising industry. 



As a single illustration of this point, let us take the teeming animal 

 life of the Antarctic. Those who have seen illustrations of recent 

 explorations near the South Pole were certainly impressed with the 

 enormous fecundity of animal life in that region. It is strange 

 therefore to note that this life is confined almost entirely to its 

 waters; to learn that there are no land birds, no land animals, nor 

 insects. This is because there is no plant life upon the shore. All 

 bird life, all animal life is marine, penguins, gulls, petrels, and 

 a long list of strictly aquatic animals. Now, in these waters of the 

 Antarctic the plant life that is most prominent is the diatom. This 

 plant, more than all others, is the explanation of the teeming life 

 that inhabits those remote seas. The writer in investigating the 

 diatoms of the Shackleton Expedition to the South Pole, found in 

 most of the samples collected a larger percentage of diatoms than in 

 any other samples known. Some dredgings made at McMurdo Bay 

 were found to be at least 50 per cent edible diatomaceous material. 

 No wonder therefore that the lower animal forms swarm in these 

 waters and that the carnivorous animal forms of larger bulk are so 

 prolific ; for between them and extinction there stands the abundant 

 and ever-present supplj^ of plant food represented by the diatom 

 flora. 



Note. — In the accompanying illusti-ations, with the exception of two figures, I am in- 

 debted for the use of the original photographs from nature, to the Hon. Alvey A. Adee, 

 Washington, D. C. The magnifications of the group lUustration is approximately 6Q 

 fliameters, of the others tvQva, 600 to 750 diameters. 



