34 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



frustule. In side (girdle) view the three apices are seen to be very 

 blunt, with a hemispherical end, back of which is the curved line of 

 irregular beads above mentioned. The outer part of the apices run- 

 ning vertically down from the three processes to the girdle are but- 

 tressed by a slight fold or extension of the valve; the vertical sides 

 of the valve (between the three apices) are scantily marked with 

 small irregular beads or blotches. 



Diameter 0.0612 mm., depth of valve (face to girdle line) 0.030 mm. 



Type.— -Cat. No. 43587, U.S.N.M. 



BIDDULPHIA ANTILLARUM (Cleve) Boyer 



(Cleve, Diat., W.I., pi. 5, fig. 29; Schmidt, Atlas, pi. 99, fig. 14.) 

 De Toni resurrects for this and a few other unmistakable Biddul- 

 phiae Ehrenberg's impossible genus, Amphipentas, stressing the acci- 

 dental five-angled form of some individuals that differ in no other 

 respect from those in the same gathering having three or four angles, 

 a process that reduces the concept, species, to an absurdity. Some 

 examples, besides the above, are his A. quinquelobata, A. godeffroyi, A. 

 campechiana, and the unimportant variety of Trigonium arcticum 

 (Brightwell) Cleve, which is called Triceratium cyclamen Brun in 

 Schmidt's Atlas (pi. 165, fig. 5). (See De Toni, Syl. Alg., p. 910.) 



BIDDULPHIA AURITA (Lyngbye) Brebisson 



(Smith, Brit. Diat., pi. 45, fig. 319; Van Heurck, Synopsis, pi. 98, figs. 4-9.) 



A number of varieties of this inconstant and prolific species was 

 found. 



BIDDULPHIA BALAENA (Ehrenberg) Brightwell 



See Trigonium balaena (Ehrenberg) Cleve. 



BIDDULPHIA BALEARICA (Cleve and Grunow) Mann 



(Cleve, New and Little Known Diatoms, pi. 6, fig. 73; Schmidt, Atlas, pi. 97. 

 figs. 20, 21.) 



The reductio ad dbsurdum of De Toni's assignments of certain forms 

 to " Ampliipentas," mentioned under B. antillarum above, is his 

 placing two figures of this species (Schmidt, Atlas, pi. 98, fig. 20) in 

 AmpJiitetras and (pi. 98, fig. 21) in AmpMpentas. 



BIDDULPHIA BICORNIS Cleve 



See under B. dubia (Brightwell) Cleve 



BIDDULPHIA BIROSTRUM Brun 



(Brun, Espec. Nouv., p. 11, pi. 12, fig. 10.) 



This has rather close resemblance to B. aurita 



