182 



DE. Q. H. rOWLEE — BISCATAN PLAJSTKTON : 



NOTE ON THE DISTEIBUTION OF THE MEDUSA. 



Bi/ G. Herbeut Powler, F.L.S. 



All specimens of Medusse, liowevei* greatly damaged *, were as far as possible picked 

 out from the various hauls and submitted to Mr. Browne. Three species occurred with 

 sufficient regularity to allow of their being dealt with statistically f in the manner 

 attempted for some other groups in these E-eports. 



Rhopalonema cceruleum, Haeckel. 



0) 



a 



d 

 o 



o 



g 

 ^ 







25 



50 



75 



100 



150 



200 



250 



300 



350 



s 



o 

 o 

 o 



o 



ft 



o 



3 

 a 



u 



3 



o 





o 



<L> 



en 



(U 

 be 



It was not taken in any closing-net, and may fairly be set down as a purely 

 epiplankton species, Avith a maximum distribution at about 50-100 fathoms. Nowhere 

 plentiful, it was least so at the surface, of all the five epiplankton zones investigated. 



Aglantha rosea (Forbes). 



\ 



/ 9, "3 



ft 



3 

 -3 



• iQcidentally it is worth noting that of 27 specimens so damaged as to be gencrically unrecognizable, 19 

 (70 per cent.) occurred in the fire serial hauls 36 g to I — a fact to be considered by those who advocate " the differential 

 method of serial tow-nets " for the study of mesoplankton. 



t In the following tables the usual time-factor has been employed (p. GO, note); the 9 hauls with a net of 

 180 meshes per linear inch have been included, as having caught medusoe, and averages have been struck over all 

 hauls at the depth mentioned, not merely over those in which the species occurred. 



X These tables are to be read as a sentence from left to right. 



