SPHAERONECTES. 183 



(Monophyes) princeps Haeckel, which share the generic characters. According 

 to Schneider ('98) all but princeps are merely members of one varietal series. 

 I very much regret that I have been unable to study actual specimens referable 

 either to irregularis or to brevitruncata, but judging from my examination of 

 kollikeri, and from the various pubUshed descriptions, I am convinced that 

 though a reduction of species is called for, Schneider has gone too far. 



The most cursory study shows that gracilis and kollikeri are very closely 

 related to each other. Chun who believes that they are distinct, gracilis being 

 an Atlantic, kollikeri a Pacific form, maintains ('92, p. 86) that they can be 

 separated by the somatocyst, which turns downward (toward the bell opening) 

 in kollikeri, upward in gracilis. To this Schneider has replied that he has 

 observed the ''kollikeri" form at Naples, while Agassiz and Mayer ('99) have 

 figured a specimen from the Fiji Islands with the typical "gracilis" somatocyst, 

 and Mayer (:00, p. 74) states that "there appears to be much individual varia- 

 bility in respect to the curvature of the phyllocyst in the Pacific species." 



I have studied this character in the series listed below, finding, witli 

 Schneider, that it is variable. In general, small specimens are of the "gracilis," 

 larger ones of the "kollikeri", type. In many of intermediate size the somato- 

 cyst is horizontal but in one of the largest individuals it turns sharply upward. 

 It is evident from these facts that this character cannot serve as the basis for 

 specific separation; and therefore gracilis and kollikeri must be united. As 

 Chun ('92) pointed out, the Eudoxids of this compound species had been de- 

 scribed by Will as Ersaea truncata long before the discovery of the polygastric 

 state, and Will's figure ('44, pi. 2), is so satisfactory that this conclusion may 

 safely be adopted. Chun relegated this early name to the synonymy of S. 

 gracilis, but, as Schneider has more recently remarked, the rules of zoological 

 nomenclature require that it be applied to the species as a whole. S. irregularis 

 and brevitruncata are another pair of closely allied forms. According to Chun 

 they are separated from each other by the very much reduced somatocyst of 

 the former, and the very short stem and small number of groups of appendages 

 in the latter. But Schneider has pointed out that the last character is of very 

 doubtful importance, in view of its variability in various Diphyids; a varia- 

 bility probably connected with the setting free of the groups of appendages. 

 As to the size of the somatocyst, the importance of this character depends 

 wholly on its constancy. Unfortunately this has never been tested; but the 

 difference in this respect between irregularis and brevitruncata is so slight that 

 it suggests varietal, rather than specific separation. On the whole, then, the 



