256 DIPHYES FOWLERI. 



to the base; there are no laterobasal teeth and the dorsal tooth is represented 

 merely by a slight prominence of the dorsal angle, while the very short conical 

 hydroecium lies wholly below the level of the bell-opening. But it is separated 

 from subtiloides by two characters which are sufficient basis for specific sepa- 

 ration, since they have proved constant on the considerable series of the two 

 species which have yet been studied (110 subtiloides, Q7 fowleri). 



In the first place, the dorsal wall of the hydroecium below the opening of 

 the nectosac, is entire in subtiloides (Lens and Van Riemsdijk, : 08), but in Joideri 

 it is divided into two wings of which the right hand one is the larger in those 

 from the Pacific, as in those from the Atlantic (Bigelow, :11b, p. 347). In the 

 second place the somatocyst in fowleri is pear-shaped or spherical, and occupies 

 a position transverse to the long axis of the nectophore, reaching hardly, if at 

 all, above the level of the mouth of the nectosac (Plate 8, fig. 4), instead of 

 being of the ordinary fusiform type and of considerable length as it is in subti- 

 loides. 



In the Biscayan specimens the point of attachment for the second necto- 

 phore could usually be detected, but on the fragmentary stems in the present 

 series neither this, nor any but the youngest appendages remain. My reference 

 of this species to Diphyes rather than to Diphyopsis rests on the apparent absence 

 of special nectophores in the only Atlantic specimen which still had a group of 

 appendages in an advanced state of development attached to the stem. With- 

 out knowing whether the groups of appendages remain attached permanently, 

 or whether they are set free, it is, of course, impossible to determine finally 

 whether the species belongs to the Diphyopsiinae or to the Galeolariinae. But 

 the structure of the hydroecium and the pyramidal form of the anterior necto- 

 phore indicate the former. 



The absence of basolateral teeth separates this species from Diphyopsis 

 dispar, D. chamissonis, and Diphyes bojani among Pacific species, as it does 

 from the Atlantic D. serrata Chun, and D. steenstrupi Gegenbaur. From 

 Diphyes appendiculata , Diphyopsis mitra, and Muggiaea atlantica it is easily 

 distinguished by the structure of hydroecium and somatocyst. The only 

 Pacific Diphyid or Monophyid with which it might possibly be confused are 

 Diphyes subtiloides Lens and Van Riemsdijk, and Muggiaea kochii Will, both 

 of which resemble it in the shape of the hydroecium. But from both it is sepa- 

 rated by the structure of the somatocyst, while between it and the latter there 

 is the further distinction that while in D. fmvleri the lateral ridges extend to the 

 basal margin, in M. kochii they end some little distance above that level (p. 188). 



