MARINE DIATOMS OF THE PHILIPPINE ISLANDS 95 



NAVICULA ASPERA Ehrenberg 



(Ehrenberg, Mikrogeologie, pi. 35A, sec. 20, fig. 5; Donkin, Brit. Diat., pi. 

 10, fig. 1; Schmidt, Atlas, pi. 48, figs. 2-6.) 



Many varieties of this truly cosmopolitan marine diatom occur in 

 the gatherings examined. 



NAVICULA BARBITOS A. Schmidt 



(Schmidt, Atlas, pi. 129, fig. 5.) 



NAVICULA BEYRICHIANA A. Schmidt 



(Schmidt, Atlas, pi. 69, figs. 16-17.) . 



Fricke's Index to Schmidt's Atlas incorrectly unites this with N. 

 gemmatula Grunow (see the latter in Schmidt, Atlas, pi. 13, figs. 20- 

 21). It has far more affinity with N. crabro (Ehrenberg) Kiitzing. 



NAVICULA BICLAVATA Cleve and Grove 



(Le Diat., vol. 1, p. 66, pi. 10, fig. 7.) 



Resembles N. clavigera Cleve in Naviculoid Diatoms, volume 1 

 page 56, plate 1, figure 3. 



NAVICULA BIFORMIS (Grunow) Mann 



Plate 20, figs. 6, 7 



(Grunow, Neu Ung. Diat., pi. 13, fig. 7; Peragallo, Diat., France, pi. 7, fig. 5; 

 Greville, So. Pac. Diat., pi. 4, fig. 13.) 



There is no more reason for making a new genus, Mastoneis, for 

 this diatom because of its double markings, than for the same reason 

 to put into new genera N. heyrichiana A. Schmidt ; or those double- 

 marked Coscinodisci: C. asteromplialus Ehrenberg, C. convexus A. 

 Schmidt, and C. liangulatus A. Schmidt, the elaborate beading 

 within the network of which is lacking in most species of Coscinod- 

 iscus. Both Grunow and Greville assign this Navicula to Stauroneis, 

 because of its obscure stauros. As Cleve points out, it also has a 

 sort of family resemblance to Mastogloia. 



NAVICULA BIGEMMATA, new species 



Plate 21, fig. 1 



Valve fusiform, with acute apices, covered with radial (not trans- 

 verse) rows of fine beading, the beads irregularly spaced, so that. the 

 valve presents a wavy, shagreenlike appearance; a distinct line run- 

 ning on each side of the rhaphe, in general midway between it and 

 the margin, but at the center curved rapidly inward toward the 

 central nodule and having at this inner point a distinct bead, one 

 therefore on each side of the central area ; the portion of the valve 

 included within these hyaline lines is slightly more elevated than the 

 outer portions, as in Navicula carinifera Grunow; a hyaline band 

 crosses the center between the two beads; the rhaphe is straight. 

 35035—25 7 



