230 • TIIE MEDUSAE. 



(1,500-900 meters), and Rhopalonema relation at 165-105 fathoms (300-200 

 meters). The following captures are recorded by Browne (: 06), from the 

 cruise of H. M. S. " Research " in the Bay of Biscay : — Periphylla, 400-300 

 fathoms, and Atolla bairdii, 1,500-750 fathoms. In addition to these two 

 intermediate genera, one well-known surface form, Aglantha rosea, was also 

 taken in eight closing-net hauls, as follows: — 150-50 fathoms, seven speci- 

 mens ; 200-100 fathoms, five specimens ; 300-200 fathoms, one specimen ; 

 500-400 fathoms, two specimens; 750-500 fathoms, 1 specimen, 1,000-500 

 fathoms, 1 specimen ; 1,250-1,000 fathoms, one specimen. This was the 

 commonest epiplanktonic species of the Expedition, and for this reason it is 

 probable, as Fowler (: 06, p. 183) has suggested, that the deeper captures 

 were merely dead specimens sinking to the bottom ; the species, however, 

 was apparently alive down to 100 fathoms. A large number of closing-net 

 hauls have been made by the "Princess Alice," those containing Medusae 

 from known depths (Maas, : 04 c ) being 1,700 meters, Atolla and Agliscera ; 

 300-350 meters, Phialidium ; 800 meters, Periphylla; 1,000 meters, Peri- 

 phylla ; and 781 meters, Aeginura. During the " Albatross " expedition of 

 1904-05 the following closing-net captures were made: — at Station 4668 

 Tanner net towed, at 300 fathoms, Halitrephes and Rhopalonema, the latter 

 too fragmentary for specific identification ; Station 4672, Tanner net 

 towed, at 400 fathoms, Aeginura, Atolla, Crossota, Aegina. Both the Chun- 

 Petersen and Tanner nets were used on other occasions, but only in these 

 two hauls were Medusae taken. 



When these various closing-net hauls are analyzed it appears that they 

 are not such strong evidence in favor of abyssal occurrence in truly 

 oceanic areas as might at first be supposed. Thus, two of the " Princess 

 Alice " captures, those of Periphylla from 800 and 1,000 meters were 

 within the Mediterranean, an enclosed sea in which the temperature con- 

 ditions are very different from those of oceanic regions ; and the deepest 

 haul, 1,700 meters (about 880 fathoms), was made only some fifty miles off 

 tin- coast of Spain. More strictly oceanic is the record of Aeginura, from 

 about 420 fathoms. Neither of the " Valdivia " records are from very great 

 depths, am! the greatest, Periphylla, from between 540 and 810 fathoms, 

 is based on a specimen so fragmentary that it is questionable whether it was 

 nol dead and Binkingai the time of capture. Both the " Albatross " records, 

 on'- <ii which comprises the greatest number of different genera of Medusae 

 yet taken in one haul of a closing net, are from moderate depths (300 and 



