20 A HISTORY OF EECEKT CEUSTACEA 



found a cumacean as low down as 2,050 fathoms, bat some ^ 

 years earlier the Swedish Spitzbergen expedition obtainea ,, 

 the appropriately named Diastylis stygia, from the still lower 

 deep of 2,600 fathoms. The Isopoda extend down to Z,740 

 fathoms, the Amphipoda possibly, but by no means cer- 

 tainly, to 2,500. Among the Entomostracans, a Phyllo- 

 carid species came from 2,550 fathoms, Ostracoda from 

 2,750, the strange copepod, Pontostratiotex abyssicola, 

 Brady, from 2,200, and a parasitic copepod, Lerncea abys- 

 sicola, was attached to a deep-sea fish brought by the trawl 

 from 2,400 fathoms. Lastly, of the Cirripedes the great 

 Scalpellum regiwn was dre'dged from a depth of 2,800 

 fathoms, the character of these animals giving more cer- 

 tainty than can be had with free-swimming Crustacea, 

 that tlie specimens actually came from the depth assigned. 

 In the use of trawls and di-edges with open mouths, there 

 is always a chance that specimens may be captured in the 

 course of lowering or hauling in the instrument, instead of 

 while it is being dragged along the ocean floor. By this 

 means the record of the occurrence of specimens at as- 

 tonishing depths is left open to some question. Yet on 

 the whole there is fair reason to believe that most of the 

 principal groups of Crustacea have representatives capable 

 of supporting existence in regions of dense gloom, with 

 a temperature icily cold, and under a column of water 

 from two to three miles in height. Many species, indeed, 

 of the Crustacea show a preference for a frigid climate, 

 since where this condition prevails their swarms are far 

 vaster and their bodies more bulky and solid than in 

 waters less cold. These Polar forms, therefore, find no 

 inconvenience, but the reverse, in the unheated tempera- 

 ture of the great depths, and though probably many of 

 them could not possibly pass the tropical waters at or near 

 the surface, far down there is a suitable water-way for 

 them from one pole of the earth to the other. 



It is rather the task of national expeditions than of 

 any private collector to procure the exceptional forms 

 which the remotest abysses of the sea have yielded and 

 may be expected still from time to time to yield There 



