ANTARCTIC MARINE 

 FREE-LIVIXG NEMATODES 



OF THE 



SHACKLETON EXPEDITION 



BY N. A. COBB 

 CONTRIBUTIONS TO A SCIENCE OF NEMATOLOGY l 



Nematodes are so frequent in the Shackleton collections as to prove 

 the seabottoms of the farthest south to swarm with these little beings. 

 Hundreds of them, male, female and young, were taken from a mere 

 thimbleful of the dredgings. The same tale comes from stations wide 

 apart. Countless myriads find sustenance in these cold dark depths, 

 and must in their turn be devoured by larger forms, until the series 

 culminates in herds of seal and schools of whale. "All that in them is," 

 takes on added meaning! 



Whence do these nematodes derive their sustenance? The stomachs 

 of a number of the species contain diatoms with such regularity as to 

 leave no doubt that these microscopic plants constitute a main food 

 supply. The undigested frustules of the diatoms are voided and go to 

 make up the permanent sea floor, so that the interesting little creatures 

 whose portraits follow, or at least a part of them, assist in building 

 what some future epoch may disclose as dry land formations of diato- 

 maceous earth as remarkable as those of the United States or those 

 of Tripoli. Some of the other species appear to be predacious, though 

 none belong to the truly carnivorous group of the Enoplidae. No doubt 

 the greater part of the species are vegetarian. 



These antarctic species are on the whole somewhat smaller than those 

 of warmer seas, but one of them, that mentioned last, is a veritable 



1 N ematology a contraction of Nematodology. The founding of this branch 

 of science, on a par with Entomology for example, is fully justified by the fact 

 that the Nematodes constitute such a distinct and highly characteristic group of 

 organisms, containing an enormous number of species readily susceptible of 

 division into definite Orders, some of which are of great economic importance. 



