246 DIPHYOPSIINAE. 



from that of steenstrupii, does not state what the difference is. But the fact 

 that our collection of bojani shows that neither the number of rows at the apex, 

 nor the relative size of the lateral teeth, mentioned by Chun as features in which 

 the two differ, is as important as he thought, suggests that the two are identical. 

 I should not be surprised if the Pacific bojani and the Atlantic steenstrupii and 

 serrata eventually prove to belong to one species. But whether this is the case 

 can only be determined by a fresh examination of Atlantic specimens, and 

 unfortunately there have been none available. 



Diphyes coniorta Lens and Van Riemsdijk is a well-characterized species, 

 easily distinguished from all other Diphyopsiinae by a peculiar asymmetry of 

 the somatocyst. 



In addition to Diphyopsis dispar, Diphyes appendiculata, and the puzzling 

 D. steenstrupi-serrata group, only three Atlantic species deserve definite 

 recognition. These are Diphyes arctica Chun, D. suhtilis Chun, and D. fowleri 

 Bigelow. The probable identity of Diphyopsis hispaniana Mayer and D. mitra 

 is noted above. On the other hand there is a possibility that Doromasia pida 

 Chun may belong here (p. 265). D. fowleri is here recorded from the Pacific and 

 the collection contains one Diphyid, D. spiralis (p. 249), described as new on 

 account of the remarkable spiral torsion of the entire superior nectophore. 



The corm, or the secondary nectophore, is so often destroyed in preserved 

 specimens of Diphyes and Diph3'opsis that it would be a great convenience to 

 find a set of characters, sufficient for specific identification in the anterior necto- 

 phore alone. As it turns out, such are afforded by general form within certain 

 limits, by the number of ridges at the apex, by whether their number is constant, 

 by the presence or absence of basodorsal and basolateral teeth, and bj- the com- 

 parative length of the hydroecium. Somewhat to my surprise the latter proves 

 to be one of the most constant characters. 



The following kej^ to the species of Diphyopsiinae is based upon these 

 features. 



Key to the Species. 



1. With prominent basolateral and smaller dorsolateral teeth. 

 A. 5 (or 4) ridges at the apex. 



a\ Somatocyst long; general form very broad; nectosac ending dis- 

 tally in a tubular coecum. 

 D. dispar Chamisso and Eysenhardt. 

 a . Somatocyst long; general form, narrow; nectosac fusiform at 

 the apex; ridges at the apex either 5 or 4; lateral teeth very long. 



