MARINE DIATOMS OF THE PHILIPPINE ISLANDS 121 



smiihii Brebisson (Donkin says, " Less granular"), whereas this species 

 is much more sharply cut; N. aestiva's rows of beading are less curved 

 as they approach the apices of the valve, and it has a more spindle- 

 shaped median area, the ends of which are not set back from the ends 

 of the valve. (See Donkin, Brit. Diat., p. G, pi. 1, fig. 13; also 

 Schmidt's questionable figure of N.fusca Gregory in Schmidt's Atlas, 

 pi. 7, fig. 4, comparing these with the typical figure of N. fusca in 

 Gregory's Diatoms of the Clyde, pi. 9, fig. 15.) 



This species is quite rare. 



Type.— -Cat. No. 43662, U.S.N.M. 



NAVICULA SMITHII Brebisson 



(Schmidt, Atlas, pi. 7, fig. 19; Van Heurck, Synopsis, pi. 9, fig. 12; Supp., pi. 

 B, fig. 23.) 



Next to the figure 8 forms of Navicula represented by N. crabro, the 

 long elliptical form, of which this species may be taken as the model, 

 is the most frequent shape of marine Naviculae, both as to the abun- 

 dance of individuals and the number of different species. Conse- 

 quently much confusion exists because of the careless multiplication 

 of new names, and some of the older valid species seem thereby to 

 have lost any satisfactory boundary lines of demarcation. This is 

 particularly true of N. smithii, N. fusca, N. elliptica, etc. A discus- 

 sion of this subject has already been given under my new species, 

 N. ingens. 



NAVICULA SPECTABILIS Gregory 



Plate 27, figs. 1-2 



(Gregory, Diat., Clyde, p. 9, pi. 9, fig. 10; Donkin, Brit. Diat., pi. 2, fig. 5; 

 Schmidt, Atlas, pi. 3, figs. 20-21.) 



A Philippine Islands form, not far from the typical one of Gregory's 

 beautiful species, is here illustrated for comparison with some new 

 species which simulate but do not truly agree with it. 



NAVICULA SPICULIFERA, new species 



Plate 26, fig. 8 



Valve flat or barely convex in the middle but strongly convex toward 

 the sides; somewhat spindle-shaped but with very blunt rounded 

 ends; marked with strong, widely spaced and perfectly smooth costae 

 inclined diagonally outward, their inner ends some distance from the 

 rhaphe line ; rhaphe strong, flanked by a faint elevated ridge on either 

 side, its median ends well separated, its outer ends some distance back 

 from the convex apices of the valve, and each ending in (or adjacent 

 to) a small spine; the central nodule slightly depressed. 



Length, 0.083-0.084; width, 0.021-0.025; 6-6.6 lines in 0.01 mm. 



This species is near to Schmidt's Atlas, plate 47, figure 34, incor- 

 rectly named N. impressa Lagerstedt, and equally incorrectly renamed 



