16 



HJALMAR BROCH. 



[REP. OF THE "MICHAEL SARS" NORTH 



DISCOPHORA. 



Pelagia Peron and Lesueur. 



A great many species of Pelagia have been described, 

 bat they have gradually been reduced, and recent authors, 

 like Vanhoffen, Maas, Browne and Bigelow, doubtfully 

 acknowledge three species, viz. Pelagia noctiluca Peron 

 and Lesueur', P. perla (Slabber) and P. panopyra Peron and 

 Lesueur. These naturalists seem to agree in their views, 

 and doubt whether the three species really represent more 

 than geographical forms ("varieties"). 



Recent writers agree with Vanhoffen 1 ) that "Eine 

 Revision der Pelagienarten muss aber einstweilen auf- 

 geschoben werden, bis genugend umfangreiches Material 

 aus alien Meeren vorliegt." We shall probably have long 

 to wait for this revision, if investigators follow the example 



set by previous authors, most of whom, instead of giving 

 a detailed account of the material at their disposal, have 

 given general reasons for using the names noctiluca, perla 

 or panopyra, the main reason apparently being that the 

 specimens were taken in such or such an ocean. Maas 

 calls attention to the relative development of the mouth- 

 arms and manubrium, which latter seems to differ in the 

 specimens obtained by the "Siboga" 2 ) and in those from 

 the Atlantic or Mediterranean. 3 ) 



Our knowledge has not advanced much since 

 Vanhoffen wrote the above sentence in 1902, and 

 if the questions relating to the separation of the spe- 

 cies of Pelagia are to be solved, it will be necessary 

 for every investigator to give detailed descriptions of 

 his material, and especially to study the variations 

 thoroughly. 



Nr. 



D. 



M. 



A. 



: Nr. 



D. 



M. 



A. 



Nr 



D. 



M. 



A. 



Nr. 



D. 



M. 



A. 



Nr. 



D. 



M. 



A. 



1 



2 



0-5 



-+- 



36 



7 



3 



2 



71 



10 



2 



3 



106 



14 



4 



7 



141 



22 



5 



12 



2 



2 



0-5 



+ 



37 



7 



2 



3 



72 



10 



3 



3 



107 



14 



3 



5 



142 



23 



4 



? 



3 



2 



0-5 







38 



7 



2 



2 



73 



10 



3 



5 



108 



14 



4 



9 



1-13 



23 



8 



15 



4 



2 



0-5 



-L 



39 



7 



2 



2 



74 



11 



3 



5 



109 



14 



4 



6 



144 



24 



4 



7 



5 



2 



C-5 



+ 



40 



7 



2-5 



2 



75 



11 



2 



3 



110 



14 



4 



4 



145 



24 



4 



? 



6 



2 



0-5 



-f- 



41 



7 



2 



2 



76 



11 



3 



2 



111 



15 



5 



7 



146 



24 



5 



10 



7 



2 



0-5 







42 



8 



2 



2-5 



77 



11 



3 



6 



112 



15 



3 



7 



147 



25 



7 



18 



8 



3 



0-5 







43 



8 



1 



3 



78 



11 



4 



5 



113 



15 



4 



1 



148 



25 



5 



6 



9 



3 



0-5 



+ 



44 



8 



3 



2 



79 



11 



3 



3 



114 



15 



5 



5 



149 



25 



6 



8 



10 



3 



• 0-5 



+ 



45 



8 



3 



3 



80 



11 



3 



3 



115 



15 



5 



? 



150 



25 



6 



8 



11 



3 



0-5 







46 



8 



2 



2 



81 



11 



3 



7 



116 



15 



3 



6 



151 



26 



8 



20 



12 



3 



f-5 







47 



8 



2 



2 



82 



11 



3 



5 



117 



16 



5 



8 



152 



26 



7 



7 



13 



3 



0-5 







48 



8 



2 



2 



83 



12 



4 



5 



118 



16 



4 



8 



153 



26 



6 



16 



14 



3 



0-5 







49 



8 



2 



2-5 



84 



12 



4 



4 



119 



16 



4' 



2-5 



154 



28 



6 



18 



15 



3 





_!_ 



50 



8 



2 



1-5 



85 



12 



4 



6 



120 



16 



4 



9 



155 



29 



8 



15 



16 



3 





_1_ 



51 



9 



3 



3 



86 



12 



3 



3 



121 



16 



3 



5 



156 



32 



10 



19 



17 



3 





+ 



52 



9 



3 



4 



87 



12 



3 



4 



122 



16 



4 



6 



157 



32 



6 



21 



18 



3 





+ 



53 



9 



2 



4 



88 



12 



3 



3 



123 



17 



4 



9 



158 



32 



9 



31 



19 



3 





_1_ 



54 



9 



25 



3 



89 



12 



3 



7 



124 



18 



6 



7 



159 



33 



4 



10 



20 



3 





_L_ 



55 



9 



2 



4 



90 



12 



6 



5 



125 



18 



3 



7 



160 



33 



8 



8 



21 



3 







56 



9 



2 



2-5 



91 



12 



4 



4 



126 



19 



4 



11 



161 



36 



7 



20 



22 



3 





-+" 



57 



10 



3 



3 



92 



12 



3 



3 



127 



19 



3 



7 



162 



37 



10 



25 



23 



3 





1 



58 



10 



3 



4 



93 



12 



3 



5 



128 



19 



5 



? 



163 



39 



10 



20 



24 



3 



1-5 



+ 



59 



(0 



2 



4 



94 



12 



2 



5 



129 



19 



5 



8 



164 



40 



11 



21 



2-5 



4 



2 







60 



10 



3 



4 



95 



12 



4 



6 



130 



19 



4 



3 



165 



45 



8 



26 



26 



4 



2 



1 



61 



10 



3 



5 



96 



12 



2 



? 



131 



19 



5 



9 



166 



45 



8 



23 



27 



5 



2 



1 



62 



10 



3 



5 



97 



13 



3 



3 



132 



20 



5 



12 



167 



46 



11 



26 



28 



5 



2 



1 



63 



10 



3 



4 



98 



13 



4 



5 



133 



20 



7 



10 



168 



52 



15 



35 



29 



6 



2 



1 



64 



10 



3 



4 



99 



13 



4 



3 



134 



20 



4 



? 



169 



56 



7 



35 



30 



6 



1 



0-5 



65 



10 



3 



2 



100 



13 



4 



? 



135 



20 



4 



? 



170 



78 



19 



48 



31 



6 



1-5 



1 



66 



10 



3 



3 



101 



13 



4 



4 



136 



21 



5 



ii 



171 



80 



20 



54 



32 



6 



2 



2 



67 



10 



2-5 



1 



102 



13 



4 



7 



137 



21 



4 



14 



172 



110 



17 



65 



33 



7 



2 



2 



68 



10 



2 



2-5 



103 



14 



3 



8 



138 



22 



6 



8 



173 



117 



30 



80 



34 



7 



2 • 



2 



69 



10 



2 



2 



104 



14 



4 



5 



139 



22 



6 



? 



174 



124 



24 



92 



35 



7 



2 



1 



70 



10 



2 



3 



105 



14 



3 



7 



140 



22 



4 



9 











Table of measurements in mm of the "Michael Sars" specimens of Pelagia peila (D = total diameter of the disc, M = length of the manu- 

 brium, A = length of the mouth-arms. A -j- means that the arms are indicated, although not sufficiently large to be measured.) 



') Die Acraspeden Medusen. (Wiss. Erg:bn. Deutschen Tiefsee-Exped., Bd. III). Jena 1902, p. 37. 

 2 ) Die Scyphomedusen der Siboga-Expedition. (Siboga-Expeditie, Monogr. XI). Leiden 1903, p. 29. 



:; ) Meduses provenant des campagnes des yachts Hirondelle et Princesse-Alice. (Res. Camp. Scient, Prince de Monaco, 

 Fasc. XXVIII). Monaco 1904, p. 56. 



