164 mr. e. t. browne — biscatan plankton : 



Introduction. 



The Medusse whicli Dr. Eowler collected during his expedition to the Bay of Biscay in 

 1900 were kindly handed over to me for examination. I have worked through his 

 collection with much interest. After working several years on the medusoid fauna of 

 the British Isles, I was particularly anxious to learn something ahout the medusse 

 which live in the Atlantic heyond our hundred-fathom line. There have been many 

 expeditions to the deep water oflF our western coasts, hut, for some reason or other, the 

 medusse have usually been forgotten, so that the records of capture beyond the hundred- 

 fathom line are rather scarce. 



Dr. Powler selected the northern side of the Bay of Biscay for his explorations, 

 and worked in the neighbourhood of latitude 47° N. and a little to the westward of 

 longitude 7° W., where he was able to let down his nets to 2000 fathoms. He made 

 138 separate hauls with tow-nets, and out of these I received specimens from 88 hauls. 



I have been able to identify fifteen genera and ten species, but have failed to identify 

 specimens belonging to several different genera owing to their mutilated condition. 

 Unfortunately, nearly all the specimens taken in the deep hauls below 600 fathoms were 

 in bad condition, and several were quite unrecognizable. 



The Trachomedusse predominated over all the other orders. Six genera were 

 recognized, and at least two more were present, but not in a recognizable condition. 

 Three species formed about 85 per cent, of the specimens in the collection. These were 

 Aglantha rosea (42 per cent.), Aglaiira hemistoma (27 per cent.), and Rhopalonema 

 coeruleum (15 per cent.). Among the rarities I may mention Trachynema eurygaster, 

 which belongs to the fauna of the Mediterranean and the warm water of the Atlantic ; 

 Colobonema sericeum, one of the new deep-sea medusa3 discovered by the ' Valdivia ' 

 in the Giilf of Guinea and the Indian Ocean; and some large adult specimens of 

 Momceonema platygonon. I expected to see at least one species of Ziriope in the 

 collection, as the species of this genus are common and widely distributed over the 

 Atlantic ; but their natural habitat is no doubt in the warm water. Occasionally they 

 do drift up the English Channel and along the west coast of Ireland. 



The Narcomedusse were uncommonly scarce. Three genera were recognized, and at 

 least two more genera from out of the unrecognizable genera may be allotted to this 

 order. There is, however, a species which I believe has not hitherto been described. 

 It belongs to the genus Cimoctantha, and the species is named in compliment to 

 Dr. G. H. Eowler. It has a number of medusa-buds showing various stages of develop- 

 ment upon the pouches of the stomach. Other species of Cunoctantha and Cmiina are 

 known to have medusa-buds ; but at this stage the buds are really parasites, developing 

 3ither directly or indirectly from the eggs of another medusa, or they may arise from 

 jurious neutral amoeboid cells such as those which Metschnikoff has described for Cunina 

 tv^oboscidea. The medusa-buds in this new species develop from outgrowths of the 

 walls of the stomach, presenting a straightforward case of asexual gemmation, such as is 

 foimd in some of the Anthomedusse. 

 The Scyphomedusge were also very scarce. The collection contains a single specimen 



