ERSAEA BOJANI. 265 



used to separate an Atlantic from a Pacific species, i. e. sliape of tlie somatocyst, 

 and degree of serration of the bract, are sufficiently stable to be of value for diag- 

 nosis, because in their material they found every gradation between the two 

 supposed forms. In this I entirely agree with them. Thus in some specimens 

 of the present series, the somatocyst is symmetrically rounded; in some it has 

 the asymmetrical lateral process which, according to Chun, characterizes the 

 Pacific species. E. bojani has been described so well by Huxley, by Chun, and 

 by Lens and Van Riemsdijk, that no account is necessary here. It is of a very 

 characteristic form, easily recognizable by the transverse phallocyst, and by 

 the conformation of the base of the special nectophores. The accompanying 

 figures may serve for identification. 



Chun identified the Pacific form with his Doromasia bojani, which now 

 proves to be a Diphyid: but the union of the two rested merely on supposition. 

 According to him the Atlantic form is the free Eudoxid of Doromasia picla Chun; 

 an identification generally accepted. The association of E. bojani with Doro- 

 ynasia picta is made certain, according to Chun ('92, p. 100) by the resemblance 

 between its tentilla and bract and the corresponding structures in the oldest 

 cormidia of Doromasia. He does not seem to have observed its actual develop- 

 ment from the latter. The tentilla do not afford a safe clue, for, so far as they 

 are concerned, the Eudoxid might belong to any one of several Diphjaids. When 

 we compare Chun's figure of the bract of Doromasia ('92, taf. 8, fig. 3) with the 

 bract of the Eudoxid we find that the resemblance is certainly no closer than 

 between it and the bract of the Pacific Dipkyes bojani. Indeed the bracts of 

 Doromasia and of Diphyes bojani resemble each other so closely, even in details, 

 that they might well belong to one species. In short, then, Ersaea bojani 

 might as well be the Eudoxid of one as of the other. The case is further compli- 

 cated by the fact that not only in the form of the bract, but in every other respect 

 Doromasia picla and Diphyopsis dispar resemble each other so closely that there 

 would be slight reason for separating them, were it not that one is a Monophyid, 

 the other a Diphyid. The evidence that Doromasia has only one nectophore 

 is that Chun ('92, p. 95) foimd no posterior one, f)r even the bud for one, in anj' 

 of the forty specimens which he studied alive. This evidence is valuable; 

 but inasmuch as Chun's specimens were all young as shown by the fact that 

 very few of them had as many as four developing Eudoxids, and since Mayer 

 (:00) has recently noted a form from the West Indies resembling Doromasia 

 in every respect except that it has two bells,' it is not conclusive. I may point 



' Dr. Mavcr in conversation hsus coiifirmptl this. 



