344 ME. HENET B. BIGELOW — BISCAY AN PLANKTON : 



The earliest name, elongata, cannot be used, since it was preoccupied by Hyndman 

 for anotber DipTiyes. 



Tbis species, thanks to the peculiar form of its somatocyst, with long thread-like stalk 

 and spherical terminal dilatation, is one of the most easily recognized members of the 

 genus. Lens and Van Riemsdijk (1908) found that the form of this organ and 

 the rounded apex of the anterior nectophore were constant in a large series from Naples, 

 and the 18 specimens from the Bay of Biscay are perfectly typical so far as both 

 characters are concerned. To Chun's accounts I need only add that, in spite of a 

 shallowness of the hydroecium, so extreme that we may almost speak of its cavity as 

 entirely suppressed, its dorsal wall below the level of the opening of the nectosac is 

 divided so as to form a right and left wing, much as ia D.fowleri and in Muggicea kochii. 

 This region is not clearly shown in Chun's figure. All of the specimens were more or 

 less distorted ; in most of them the subumbrellar musculature is destroyed and the 

 entire stem with its appendages torn off. No inferior nectophores could be identified, 

 nor could I find any of its eudoxids. 



Diphyes suhtilis is one of the most common Siphonophores in the Mediterranean, where 

 it is an epiplanktonic form of regular occurrence. So far as I am aware, it has been 

 recorded in the Atlantic only from the Canary Islands, where Chun (1S88) foimd 

 it only occasionally. It is not present in the extensive West Indian collections which I 

 have examined. The present captures, all in open nets, are too few to warrant specula- 

 tion as to its bathymetric range further than to note, as rather surprising in view of its 

 previously known habitat, its absence from all the surface hauls. They show, however, 

 that it is not so exclusively a subtropical form as has been supposed, for it was taken 

 in temperatures somewhere between 62° (100 fathoms) and 66° F. (surface). 



Diphyes appendiculata, Eschscholtz. 



Diphyes ajjpendiculata, Eschscholtz., 1829, p. 138, Taf. 13. fig. 7; Huxley, 1858, p. 34, pi. 1. fig. 2 j 



K. C. Schneider, 1898, p. 85. 

 Diphyes bipartita, Costa, 1836, ' Genere Diphya," p. 4, Tav. 4 ; Chun, 1897 b, p. 24. 

 Diphyes elongata, Hyndman, 1841, p. 165, figs. 1-4. 

 Diphyes acuminata, Leuckart, 1853, p. 61, Taf. 3. figs. 11-20. 

 Diphyes sieboldii, Kolliker, 1853 «, p. 36, Tab. 11. figs. 1-8. 

 Dipjhyes gracilis, Gegenbaur, 1854 a, p. 309, Taf. 16. figs. 5-7. 

 "i Diphyes jmsiUa, McCrady, 1857, p. 174. 



In this list only the more important references are given. 



I follow Huxley and K. C. Schneider in uniting in. one species the Atlantic D. blpat^tita 

 and the Pacific D. appetidiculaia, because my examination of large series from both, as 

 well as from the Indian Ocean (Bigelow, 1904), has failed to reveal a single character to 

 separate them. 



This species and its eudoxid are so well known that I need only mention here that 

 the collection shows that the presence of only three ridges at the apex of the anterior 

 nectophore is constant, and that the fourth ridge, which arises some distance below the 

 apex, invariably becomes the left lateral. 



