MARINE DIATOMS OF THE PHILIPPINE ISLANDS 45 



BIDDULPHIA RETICULATA Roper 



(Micro. Journ., vol. 7, pi. 2, figs 14-17; Schmidt, Atlas, pi. 78, figs 21-23; 

 pi. 84, figs, 9, 15, 16; pi. 85, fig. 8.) 



The variety, subspinosa, figured in Schmidt's Atlas, plate 84, figure 

 15, also found, is questionable as belonging here. 



BIDDULPHIA RETIFORMIS, new species 



Plate 10, fig. 6 



Valve fusiform, the broad spindle made up of a very convex cir- 

 cular central part, from opposite sides of which protrude two trian- 

 gular extensions, their surfaces at a lower level than the central part 

 and ending in sharp angles from which arise two horns pointing 

 obliquely outward ; the circular central part is covered with a reticu- 

 late network of lines, set with numerous fine prickles and underlaid 

 with radiating rows of beading; the network is replaced on the two 

 extensions by three to four longitudinal ridges ; the horns are long, nar- 

 row, tapering, and enlarged at the ends. 



Length 0.056; width 0.031 mm. 



Although only a single specimen was found, I can not reconcile its 

 symmetrical form and its reticulate markings with the idea that it is 

 an abnormal two-angled specimen of B. pentacrinus (Wallich) Van 

 Heurck. 



Type.— Cat. No. 43597, U.S.N.M. 



BIDDULPHIA ROBERTSIANA (Greville) Boyer 



(Micro. Journ., 1863, p. 231, pi. 9, fig 9; Schmidt, Atlas, pi. 83, figs. 3, 5-7.) 



Both the type form and the spineless variety called inermis were 

 found. 



BIDDULPHIA ROPERIANA Greville 



(Micro. Journ., vol. 7, pi. 8, figs. 11-13; H. L. Smith, Types, No. 625; Van 

 Heurck, Synopsis, pi. 99, figs. 4-6.) 



BIDDULPHIA RUDIS, new species 



Plate 10, fig. 7 



Valve triangular, massive and practically hyaline, a few scattered 

 imperfect blotches being dimly seen on some specimens ; apices very 

 blunt, with three short stout horns of the Cerataulus pattern, ending 

 in circular disks that are inclined outward. 



As no complete frustule was found, the girdle aspect is unknown. 



Diameter (measured from one apex to opposite side) 



0.059 mm. 



There is a slight resemblance between this and the unnamed figure 

 in Ostrup, Diatoms of Siam, plate 1, figure 4. 



Type— Cat. No. 43598, U.S.N. M. 



