42 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



The form or architectural plan is carried in this and similar species 

 of BiddulpMa to so high a degree of complexity that an accurate 

 image of the specimen by means of description without the aid of 

 illustration is quite impossible. The highly elaborate ornamentation 

 of this diatom showed slight variations in the large number of speci- 

 mens obtained. 



It is related more or less closely to Triceratium partitum Greville 

 (Moebius, Diat. Taf., pi. 55, fig. 8; Micro. Journ., 1864, pi. 2, fig. 8) 

 to T. cellulosum Greville as figured by Walker and Chase (New Diat., 

 pi. 4, fig. 8), but less so with the original in the MicroscopicalJournal 

 for 1861, plate 4, figure 14, with T. expression Janisch (Schmidt, Atlas, 

 pi. 94, fig. 16) and, except for the very unlike horns, with T. mada- 

 gascarense Grunow (Schmidt, Atlas, pi. 94, fig. 15). 



Type.— Cat. No. 43595, U.S.N.M. 



BIDDULPHIA JUNCATENSIS (Grunow) Mann 



(Schmidt, Atlas, pi. 76, fig. 13.) 



This species is incorrectly united with B. (T.) inelegans (Greville) 

 by Boyer (Bidd. Forms, p. 725). It is found both in Campeche Bay 

 and the Philippine Islands, but not elsewhere. 



BIDDULPHIA JUNCTA (A. Schmidt) Mann 



(Schmidt, Atlas, pi. 98, figs. 1-3.) 



This large and handsome diatom is quite common in the Philippine 

 Islands. Its being a BiddulpMa is so evident that one wonders why 

 Schmidt did not in this instance break away from the untenable 

 arrangement of putting such forms in Triceratium. 



BIDDULPHIA MADAGASCARENSIS (Grunow) Mann 



(Schmidt, Atlas, pi. 81, fig 18; pi. 94, fig. 15; Van Heurck, Synopsis, pi. 108, 

 fig. 8.) 



This species has rather too close resemblance to T. radio-punctatwn 

 A. Schmidt (Schmidt, Atlas, pi. 94, fig. 14). 



BIDDULPHIA MEMBRANACEA Cleve 



See Trigonium membranaceum (Cleve) Mann. 



BIDDULPHIA MOBILIENSIS Bailey 



(Amer. Journ. Sci., 1845, p. 336, pi. 4, fig. 24; Van Heurck, Synopsis, pi. 101, 

 figs. 4-6.) 



The best figures for distinguishing between this and the similar B. 

 chinensis Greville are to be found in Schmidt's Atlas on plate 122. 

 Although common in Japanese waters it is rather uncommon in the 

 Philippine Islands. 



