

160 EXPEDITION OF THE "ALBATROSS," 1899-1900. 



DIPHYOPSIS APPENDICULATA. 

 ERS^EA APPENDICULATA. 



Diphyopsis appendiculata Agassiz and Mater. 



Diphyes appendiculata Eschscholtz, F., 1829; Syst. der Acalephen, p. 138, Taf. XII., Fig. 7. 

 Diphyes appendiculata Huxley, T. H., 1859 ; Oceanic Hydrozoa, p. 34, PL I., Figs. 2-2=. 



Plate 9, figs. 38, 39. 



This species was first obtained by the "Albatross" in N. hit. 17° 32', 

 W. long. 135° 40', and it continued to be abundant throughout the tropical 

 regions of the Pacific. In the Pacific species the entoderm of the polypites 

 and nematocyst batteries is milky, or slightly yellow or pink in color, while 

 in the Atlantic form the potypites are of a more or less intense green and 

 the nematocyst batteries of the tentacles are yellow or orange (see Bull. 

 Mus. Comp. Zool., Vol. XXXVII., No. 2, PI. 34, Fig. 114). A still more 

 important difference between the two species lies in the fact that in the 

 Pacific form the monogastric sexual generation belongs to the genus Erssea, 

 and lacks a manubrium within its swimming-bell ; while in the Atlantic form 

 it belongs to the genus Eudoxia, for it possesses a manubrium within its bell. 

 The Pacific form, therefore, is a Diphyopsis, while the Atlantic form belongs 

 to the genus Diphyes. 



The animal is 18-20 mm. in lens;th, and the anterior swimrnins;-bell 

 is somewhat larger than the posterior. The anterior bell is angular and 

 pyramidal and its cavity is voluminous. There are two ascending, curved 

 radial canals and a simple circular vessel. The phyllocyst is long and 

 narrow and contains an " oil globule " near its distal extremity. There is 

 a moderately deep conical hydrcecium upon the ventral face of the anterior 

 Hectophore, and the siphosome arises from its inner apex. The first appen- 

 dage of the siphosome is the large posterior swimming-bell (ps, Fig. 39). 

 This is somewhat smaller than the anterior bell, and a deep groove covered 

 by a projecting tooth runs down the side upon which the siphosome is situ- 

 ated. Indeed the siphosome lies within this groove and is protected by 

 the covering tooth. The second appendage of the siphosome is the small 

 auxiliary swimming-bell (« s, Fig. 39). Immediately below this comes a 

 cluster of immature feeding polypites, the older ones being successively 



