432 bulletin: museum of compakative zoology. 



Maas, 1909), there is nothing surprising in its occurrence in the tropical 

 Atlantic as well. And the Siphonophorae collected by the Bache are 

 not only similarly universal, within their temperature limits, in all 

 oceans (1911b; Moser, 1913a, 1913b, 1915), but most of them are 

 already known from the West Indies, the Bahamas, the Tortugas, 

 Bermuda, or the Gulf Stream. The only new siphonophore records 

 for the region in question from the Bache list are Vogtia pentacantha, 

 Vogtia glabra, Ahyla dentata, Ceratocymba sagittata, Galeolaria austraUs, 

 Chuniphyes and Stephanomia rubra. But all of these, except the two 

 new species, and Galeolaria quadridcntaia for which no locality has 

 ever been given, are already known from some part of the Atlantic. 

 Thus Vogtia pentacantha has been recorded from the Bay of Biscay 

 (Bigelow, 1911a), from the central and south Atlantic, and from the 

 Antarctic (Moser, 1913a, p. 146) ; Galeolaria vionoica from the Cana- 

 ries (Chun, 1888) ; Galeolaria aaistralis from Greenland and from the 

 north and south Atlantic (Bigelow, 1911b, " G. biloba"; Moser, 1913a, 

 p. 148), Chuniphyes from the Bay of Biscay (191 la) ; while Ceratocymba 

 sagittata is recorded by Moser (1913a, p. 149) as taken repeatedly by 

 the Gauss. And though Stephanomia rubra has not previously been 

 recorded from the Atlantic, so far as I can learn, it is known from such 

 widely separated localities as the Mediterranean and the Island of 

 Amboina (Bedot, 1896). In short, there is nothing surprising in the 

 capture of any of these holoplanktonic Medusae or Siphonophorae by 

 the Bache. However, the records have the value of actually filling 

 in a blank on the map, to which their ranges could previously be ex- 

 tended by inference only. 



A characteristic example of the holoplanktonic habit, which may 

 serve to illustrate them all in the Atlantic, is afforded by Rhopalonema 

 vclatum., which has been found all along the routes of the various deep- 

 sea expeditions of recent years, and in the Mediterranean as well 

 (Fig. 1). Its most northern records are from off the Grand Banks on 

 the west, the Bay of Biscay on the east (Browne and Fowler, 1906). 

 And it would not be surprising to find it carried even further north in 

 the warm currents in summer, especially off the European coast as 

 happens with so many other pelagic animals. 



Between 30° S.; and 40° N. in the Atlantic high seas it is practically 

 universal except in the cool coast water off eastern North America, 

 the only other important gaps in its range being the localities where 

 few, or no, plankton hauls have yet been made. In terms of tempera- 

 ture, the normal limits to its range about coincide with the surface 

 isotherms for 18° C, for the warmer months. And it, or any of the 



