MARINE DIATOMS OF THE PHILIPPINE ISLANDS 99 



NAVICULA CORPULENTA, new species 



Plate 21, fig. 4 



Valve unusually broad at the center, rapidly narrowed to the 

 rounded ends ; marked with a broad band of fine beaded lines, radi- 

 ally arranged along each side, narrowing and disappearing at the 

 margins at the point where the broad central part passes into the 

 clavate ends; these ends marked by similar beaded lines on either 

 side of the rhaphe, which gradually narrow as they approach the 

 center of the valve, and stop with the ends of the rhaphe at the 

 central nodule; the rest of the valve is hyaline, rarely rugose, thus 

 forming an oval median area within the marginal bands of beading 

 and divided by the clavate beading bordering the rhaphe. 



Length, 0.055-0.096; width, 0.038-0.056; lines, 18 in 0.01 mm. 



This minute and constant diatom is plainly of the N. clavata 

 group, but too widely divergent from it to be specifically identical. 



It is very abundant in the Philippine Islands. 



Type.— Cat. No. 43642, U.S.N.M. 



NAVICULA CRABRO (Ehrenberg) Kiitzing 



(Donkin, Brit. Diat., pi. 7, fig. 1; Schmidt, Atlas, pi. 69, fig. 1; Nordsee 

 Diat., pi. 1, figs. 5-6; Ehrenberg, Mikrogeologie, pi. 19, figs. 29a-c.) 



It is probable this variable and widely distributed diatom will 

 always present difficulties in defining its specific boundaries; for it 

 represents a group of the Naviculae that embraces more species than 

 any other, perhaps more species than any other shape of diatom — 

 that of a figure 8. But for that very reason a convenient and work- 

 able classification can be secured only by avoiding too sweeping 

 condensations. Thus, the union here of such forms as N. multicostata 

 Grunow, N. pandura Brebisson, etc., is not at all helpful. (See the 

 latter in Diat. Cherbourg, pi. 1, fig. 4; Schmidt, Atlas, pi. 11, figs 

 1-2, 4, 8-9, and the former in Schmidt's Atlas, pi. 1 1 figs. 14-20.) On 

 the other hand, the line of demarcation becomes difficult to see 

 between N. crahro and N. separabilis A. Schmidt (pi. 11, figs. 28-29) 

 despite its assertive name. 



NAVICULA CUSPIDATA Kiitzing 



(Smith, Brit. Diat., pi. 16, fig. 131; Donkin, Brit. Diat., pi. 6, fig. 6; Van 

 Heurck, Synopsis, pi. 12, fig. 4.) 



This fresh-water diatom probably came as detritus into the marine 

 samples of Philippine flora. 



NAVICULA CYCLOPS, new species 



Plate 21, fig. 5 



Valve broadly oval, ends not produced, beading of very fine lines 

 which are radial near the margin but elsewhere broken up into a 

 wavy pattern; arranged in four bands, two along the margin, about 

 one- seventh the length of the transverse axis at the center, and 



