340 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



In D. bojani the number of ridges at the apex of the superior 

 nectophore is variable, the. specimens with 3, 4, and 5, in a series 

 of 50 from the eastern Pacific, being in the proportions of about 

 1, 5, and 10. 



In the present small series there are six specimens with five ridges 

 at the apex, two with four. Individuals with four ridges at the 

 apex fall into two main classes; there may be a dorsal, one lateral 

 and two ventral, the second lateral arising from a division of one 

 of the ventrals a short distance below the apex, or there may be a 

 dorsal, two laterals and one ventral, the latter dividing into two. 

 The two Philippine specimens in question belong to class 1. In each 

 the right lateral ridge arises through a bifurcation of the right 

 ventral. Various intermediates occur, and in some specimens the 

 apex is not a point, but a flat area of appreciable size, from the top 

 of which the ridges originate; or, again, it may be represented by 

 a short transverse dorso-ventral ridge. In short, the five ridges of 

 bojani show very wide individual variability, but they always arise, 

 by whatever method, close to the apex; and, so far as my observa- 

 tions go, the dorsal ridge never branches, and always arises at the 

 apex. It is the proved variability of the ridges that has led to my 

 uniting the D. indica, D. malayana, and D. gegenbauri of Lens and 

 Van Kiemsdijk as synonyms of bojani. 



The only diphyiids with which bojani might be confused are young 

 specimens of Diphyopsis dispar; but the presence of minute teeth 

 on the dorsal hydroecial wall in bojani separates it from dispar (1918, 

 p. 424, pi. 8, figs. 3, 4). I had overlooked these teeth until Doctor 

 Moser called my attention to them in a letter. But they are shown by 

 Gegenbaur (1860, pi. 29, fig. 27) ; and the narrow outline of bojani 

 separates it at the first glance from adult dispar. 



D. bojani is widely distributed over the warmer parts of the Pacific 

 and Atlantic; it was therefore to be expected in Philippine waters. 



DIPHYOPSIS DISPAR (Chamisso and Eysenhardt) Chun. 



Diphyes dispar Chamisso and Eysenhakdt, 1821, p. 365, pi. 33, fig. 4. 

 Diphyes campanulifera Eschscholtz, 1829, p. 137, pi. 12, fig. 6. Synonymy 

 Bigelow, 1911ft. p. 257. 



Diphyopsis dispar — material examined. 



