MARINE DIATOMS OF THE PHILIPPINE ISLANDS 87 



under the generic name, Orthoneis. A careful study of both the 

 valves and these peculiar chambered annuli makes the identity of 

 the two certain. Cleve has adopted this view in his Naviculoid Dia- 

 toms, volume 2, page 142. 



MASTOGLOIA ACHNANTHIOIDES new species 



Plate 18, fig. 7 



Valve fusiform with acute apices, slightly narrowed at the middle, 

 crossed by fine and very close beaded lines, somewhat flaring on 

 either side of the central nodule, otherwise diagonally inclined from 

 the center, none trans verse ; marginal chambers small, uniform, extend- 

 ing almost to the apices; median longitudinal area very narrow, so 

 that the beading extends almost to the tortuous rhaphe. 



Length 0.051-0.084; width 0.021-0.022; 12 to 13 lines in 0.01 mm. 



Its nearest relative is M. constricta Cleve as given in Le Diatomiste, 

 page 159, plate 23, fig. 5; also in Cleve's Naviculoid Diatoms, volume 

 2, page 154; but that is a narrower and more angular form with 

 finer markings, 21 lines in 0.01 mm., which are strictly transverse and 

 with their beading so spaced as to produce wavy longitudinal lines. 

 It also has some affinity with M. fallax Cleve (Nav. Diat., vol. 2, p. 

 153, pi. 2, fig. 16) from Java, which differs from it in form and in 

 the oval character and arrangement of the beading. 



Type.— Cat. No. 43633, U.S.N. M. 



MASTOGLOIA CAPAX, new species 



Plate 19, fig. 1 



Valve broadly fusiform, apices not produced, marked with finely 

 beaded, closely set lines practically transverse, but slightly diagonal 

 toward the apices; median area very narrow; a small stauroslike 

 hyaline expansion on either side of the central nodule, made by the 

 withdrawal of the beaded lines; rhaphe slightly tortuous, delicate; 

 central and terminal nodules minute; chambers next to the margin 

 small and uniform in size, longer than wide, rounded on inner side, 

 the rows reaching to the apices. 



Length 0.087-0.101; width 0.042; 15-16 lines in 0.01 mm. 



It is nearest to the doubtfully named figure of M. affirmata Leud- 

 uger-Fortmorel in Schmidt's Atlas, plate 188, figure 31, which however 

 has coarser markings, no stauros and straight rhaphe. It may be the 

 same as the unnamed figure from Japan in Schmidt's Atlas, plate 204, 

 figure 14, as Cleve's suggestion there recorded, that it may belong to 

 M. angulata Lewis, is not acceptable. In case the marginal chambers 

 of Schmidt's Atlas, plate 187, figure 41, also unnamed, are the same 

 as the above, it could be included here as a somewhat attenuate 

 variety. 



Type.— Cat. No. 43634, U.S.N.M. 



