MARINE DIATOMS OF THE PHILIPPINE ISLANDS 103 



Length, 0.070-0.087; width, 0.016-0.017; depth of frustule, 0.043 to 

 0.051; 4.5 lines in 0.01 mm. 



This species has some affinity with those in Schmidt's Atlas, plate 

 46, figures 41-42 and 71-72, erroneously named in Fricke's Index and 

 in Cleve's Naviculoid Diatoms (p. 30), var. gregorii Ralfs of N. can- 

 cellata Donkin. But if compared with N. cancellata Donkin itself, 

 there is very little similarity, (Donkin, Brit. Diat., p. 55, pi. 8, fig. 4) 

 nor with Ralfs N. gregorii (see Pritchard, Inf., p. 901 and Gregory, 

 Glenshira Diat., p. 41, pi. 4, fig. 21, which equals Pinnularia apiculata 

 Gregory) . In face view the valve reminds one of N. impressa Lager- 

 stedt (Diat. Bonus., p. 33, pi. 1, fig. 3) the costae of which, however, 

 are smooth. In side view all resemblance disappears. 



Type.— Oat. No. 43645, U.S.N. M. 



NAVICULA FUSCA (Gregory) Ralfs 



(Gregory, Diat., Clyde, p. 14, pi. 1, fig. 15; Donkin, Brit. Diat., pi. 1, fig 5; 

 Schmidt, Atlas, pi. 7, figs. 2-4; Van Heurck, Synopsis, Supp., pi. B, fig. 24.) 



For discussion of the boundaries of this species see N. ingens, new 

 species. 



NAVICULA GEMMATA Greville 



(Greville, Cal. Guano, p. 30, pi. 4, fig. 7; Schmidt, Atlas, pi. 70, figs. 72-74.) 



Several variations from the type, as var. peristiopliora as well as the 

 type form, were found. 



NAVICULA GEMMULATA Grunow 



(Schmidt, Atlas, pi. 13, figs. 19-21.) 



NAVICULA GLABRISSIMA, new species 



Plate 22, fig. 3 



Valve wholly glabrous, narrowly oval, slightly prismatic in out- 

 line; convex; apices rounded, blunt; rhaphe strong, straight, ending 

 in beads at the apices and the center; median area on either side of 

 rhaphe very narrow 



Length, .065-0.070; width, 0.023-0.026 mm. 



This diatom gives no evidence of surface markings under the best 

 1.8 oil-immersion objective, with either direct or oblique illumination. 

 The specimens might be considered to be immature or auxisporial 

 forms were it not for the perfect finish of the entire frustules, includ- 

 ing rhaphe. Rare found only at Jolo Jolo, Sulu Islands. 



Type.— Cat. No. 43646, U.S.N.M. 



NAVICULA GRAEFFII Grunow 



Plate 22, fig. 4 

 (Schmidt, Atlas, pi. 7, figs. 5-6; pi. 8, fig. 33; and Cleve, Nav. Diat., vol. 1, p. 93.) 



Another species common to both Campeche Bay and the Philip- 

 pine Islands. It also occurs in the nearby islands of Celebes and 

 Java. 



35035—25 8 



