MARINE DIATOMS OF THE PHILIPPINE ISLANDS 113 



NAVICULA O'SWALDII Janisch 



(Schmidt, Atlas, pi. 70, fig. 46.) 



I follow here the lead of other diatomists in recording this as 

 separate from N. excavata Greville, but the two are not satisfactorily- 

 distinguishable. 



NAVICULA PACIFICA (Castracane) Mann 



(Castracane, Chall. Exp., p. 23, pi. 20, fig. 9.) 



This is placed in the genus Stauroneis by Castracane, an ill-defined 

 and to me unnecessary separation from the genus Navicula. 



NAVICULA PANDURA Brebisson 



(Brebisson, Diat. Cherb., p. 15, pi. 1, fig. 4; Schmidt, Atlas, pi. 11, figs. 1-2; Van 

 Heurck, Synopsis, pi. 9, fig. 1.) 



As stated under N. crabro (Ehrenberg) Kiitzing, I do not recognize 

 this to be a variety of that species. 



NAVICULA PARTITA, new species 



Plate 24, fig. 3 



Valve narrow panduriform, the median constriction broad and 

 gently concave ; the greatest width of each half of the valve is mid- 

 way between the center and the apex, the apical part being some- 

 what wedge-shaped; on either side of the valve extends a marginal 

 band of short, heavy costae ending inwardly in a bead, the interspaces 

 between the costae being hyaline except for an obscure rounded 

 blotch near the margin; the width of this band varies in exact 

 proportion to the width of the valve, being widest midway between 

 the center and the apices and narrowing to the middle and to the 

 apices; the longitudinal central area of the valve bisected by the 

 rhaphe line is crossed by continuations of the costae in the outer 

 bands; but these continuations are broad, flat, and indistinct; no 

 rows of beads bordering the sides of the rhaphe; a small but conspic- 

 uous rectangular central nodule; rhaphe straight, ending in beads at 

 the apices and at the center, the latter touching the rectangular 

 central nodule. 



Length, 0.104-0.107; width, 0.031-0.037; 3 lines in 0.01 mm. 



One is here reminded of N. coarctata A. Schmidt (Atlas, pi. 11, fig. 

 30, and pi. 174, fig. 22) and even more so of N. exempta A. Schmidt 

 (pi. 11, fig. 29) although the original figure of the latter in Schmidt's 

 Nordseef. Diatomaceen, plate 2, figure 5, shows less similarity. The 

 marking, especially the absence of rows of beading next to the rhaphe 

 line, sets this diatom off as a distinct species. 



Type.— Cat. No. 43653, U.S.N.M. 



