40 



PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 76 



1928, p. 122). An inspection of the type specimen, however, tends to 

 make this identity seem rather problematical on account of the fact 

 that a well developed siij)raorbital organ, quite distinct from the 

 moderate upper antorbital, apparently is to be found in the original 

 D. xmtasei. A slight damage of the type specimen has made it im- 

 possible to make out the nature or presence of the upper organs of 

 the circumorbital series on the left side of the head, but conditions 

 on the right side ^^ do, in the author's opinion, scarcely leave room 

 for any doubt as to the existence of a distinct supraorbital organ, 

 similar to the corresponding organ in I). cKrysorhynclius in shape, 

 nature, and position; but considerably smaller. Such supraorbital 

 organs have not been described for D. coeruleus, and D. watasei 

 must therefore, at least tentatively, be regarded as taxonomically 

 distinct from the former species, although agreeing very closely in 

 most other respects. 



Figure 19. — Diaphus watasei Jordan and Starks 



The original illustration (Jordan and Starks, 1904, p. 581) being 

 inadequate for showing the exact arrangement of the photophores 

 and circumorbital organs, the accompanyin,g diagram has been pre- 

 pared from the type sj)ecimen. 



PLO much nearer to the base of pectoral fin than to the lateral 

 line. 5 PO. Fourth PO elevated approximately to the level of the 

 upper PVO. VLO approximately midway between the lateral line 

 and the base of ventral fin. 5 VO. SAO nearly equally spaced in a 

 steeply inclined, straight line, the continuation of which passes well 

 behind the last F6^. AO 7 + 5. First anterior ^6> elevated to about 

 midway between the levels of the first (lower) and second SAO. 

 The posterior part of the antero-anal series is also gradually ele- 

 vated toward the Pol with which the series is practically continuous. 

 This elevation is noticeable from the fifth to the seventh antero-anal 

 organs, inclusive (fig. 19). Upper SAO and Pol more than two of 

 their own diameters removed from the lateral line. First postero- 



*' The organs in question are shown on the left side of the specimen in the accompanying 

 diagram, fig. 18, to malse the drawing harmonize with the other illustrations for the 

 present report. 



