VEKTICAL RANGE OF DEEP-SEA SWIMMING FORMS. 249 



ing from 500 to 570 fathoms, where the jsouucliugs indicated a depth of 622 

 fathoms. A red, deep-sea Peneid, belonging to the genus Gennadas was 

 found in the lower, closed part of the net.* 



There can be no doubt that the deep-sea natatory Crustacea occasionally 

 come to, or very near to, the surface. The first known specimen of Hymeno- 

 dora glacialis, a species whose rudimentary eyes and whose structure point to 

 the depths as its normal dwelling-place, was taken at the surface, off the east 

 coast of Greenland. An immature specimen of Acanthephyra agassizii was 

 caught at the surface, in a dip-net, during the cruise of the " Albatross " off 

 the east coast of the United States in 1884. This specimen was kept alive 

 for half an hour before it was put into alcohol. f A female of the neai'ly 

 related, if not identical, species, A. purpurea, was captured during the 

 "National" Expedition, swimming at a depth of less than 200 fathoms. 

 Spence Bate records a specimen of Gennadas secured at the surface on 

 the voyage of tlie " Challenger." Amalop)eneus, a genus identical with, or 

 at any rate most closely allied to, Gefinadas, was found during the "Na- 

 tional " Expedition at a depth of less than 200 fathoms. Yet the same 

 thing was captured in the closing-net between 500 and 570 fathoms (bottom 

 622 fathoms) during the " Albatross " Expedition of 1891, and between 650 

 and 750 fathoms during the " National " Expedition. The genus Eucopia was 

 first made known to science through a specimen recovered from the stomach 

 of a penguin killed in the Antarctic Sea. This specimen was presumably 

 captured by the bird in comparatively shallow water. According to Mr. 

 Agassiz's notes made on board the " Albatross," the same Schizopod was 

 captured in the open part of the Tanner tow-net between the surface and 

 300 fiithoins at Station 3414 (2432 fathoms). Another individual, as we 

 have seen above, was taken in the closed portion of the net at a depth of 

 1000 fathoms. 



Spence Bate suggested that some of the free-swimming Crustacea of 

 the deep sea may approach the surface to spawn, — a plausible theoi-y if 

 one bears in mind the sensitiveness of young animals to cold. As the bot- 

 tom Crustacea of the deep sea may be supposed, from their structure and 

 affinities, to have originated directly from littoral ancestors, so the deep-sea 

 swimming forms have pi'obably come from pelagic or surface species. It 



* At Challenger Exped. Station 207 (2700 fathoms), in the mid North Pacific, a specimen of Gennadas 

 was captured in the open tow-net which had only been lowered to within 700 fathoms of the bottom. 

 t See S. I. Smith, in Ann. Rep. U. S. Fish Comm. for 1885, p. 667, 1886. 



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