CROSSOTA BRUNNEA. 135 



VanhofFen distinguishes two species, C. brunnea, the type, and C. nor- 

 vegica, but the only distinction between the two is that the single speci- 

 men of C. norvegica " ist charakterisiert . . . bei geringerer Grosse, durch 

 weiter entwickelte Gonaden " (VanhofFen, : 02 b , p. 76), and by a slightly 

 brighter red color than that of C. brunnea, distinctions which Vanhciffen himself 

 admits are " nicht bedeutend." His main basis for separating the two seems 

 to be their geographic distribution: — "Weil ein Zusammenhang zwischen 

 den Tiefseegebieten, in denen die siidliche und die arktische Form vor- 

 kommen, nicht besteht und weil keiner unserer tiefen Vertikalnetzfange im 

 nordlichen Atlantischen Ocean uns ein Exemplar von Crossota lieferte " 

 (Vanhciffen : 02 b , p. 76). 



I must strongly protest against the use of supposed geograjjkic isolation 

 as the basis for specific separation in cases like the present in which there are 

 no structural differences of sufficient taxonomic value to separate the two 

 forms. This practice may perhaps be of service to the ornithologist, though 

 this I doubt, but when applied to Medusae it is worse than useless. The 

 assumption that no connection exists between southern and arctic " Tiefsee- 

 gebieten " is far from being proved. On the contrary, the distribution of 

 Atolla and of Periphylla, and the recent capture of Colobonema in the north 

 Atlantic suggest exactly the contrary, while evidence is continually being 

 adduced to show the general continuity, not isolation, of the distribu- 

 tion of intermediate organisms in general. Such a criterion might be of 

 service were isolation of oceanic areas established ; but until the ranges of 

 the intermediate Medusae are better known it is not only valueless but 

 misleading. Therefore, I do not hesitate to include C. norvegica as a syn- 

 onym of C. brunnea, where it should remain, at least until some actual 

 divergence is detected between the two supposed species. 



Crossota brunnea Vanhciffen. 



Crossota brunnea Vanhoffen : 02>>, p. 73, taf. 9, figs. 11-18, taf. 12, figs. 84-8S, 48, 47. 

 Crossota norvegica Vanlidffon, : 0-J b , p. 75. 



Plate 2, Fig. 7 ; Plate 45, Fig. 9. 

 Station 4646 ; 300 fathoms to surface ; 3 specimens. 

 Station 4648 ; 300 fathoms to surface ; 1 specimen. 

 Station 4650 ; 300 fathoms to surface ; 1 specimen. 

 Station 4657; 300 fathoms to surface; fragments. 

 Station 4663 ; 300 fathoms (o surface ; 2 specimens. 



