MARINE DIATOMS OF THE PHILIPPINE ISLANDS 169 



genera to accommodate one or two species that happen to vary slightly 

 in size, locality, or outline is to be seriously deprecated; and can 

 but result in confusing students and in bringing certain discredit 

 upon those who make it their business to create new genera and 

 species from insufficient material." 



TRIGONIUM FORMOSUM (Brightwell) Cleve 



(Schmidt, Atlas, pi. 79, fig. 4; Micro. Journ., 1856, pi. 17, fig. 8.) 



For a discussion of the validity of this species and its separation 

 from T. arcticum Cleve see under T. diaphanum. 



TRIGONIUM FRAUENFELDII (Grunow) Mann 



(Schmidt, Atlas, pi. 94, fig. 13; Van Huerck, Synopsis, pi. 110, fig. 10.) 



There is doubt if this can be held as anything more than a variety 

 of T. latum Greville. My specimen agrees exactly with Schmidt's 

 figure, somewhat less with that of the type figure in Van Heurck's 

 Synopsis. 



TRIGONIUM GEMINUM (A. Schmidt) Mann 



(Schmidt, Atlas, pi. SO, fig. 16.) 



This has rather disturbing affinities with that group of diatoms 

 figured on plate 80 ^f Schmidt's Atlas, with T. gibbosum as its type, 

 and for the accommodation of which Bailey himself proposed the 

 genus Lampriscus. Bearing on the suggestion, not universally 

 accepted by diatomists, see De Toni (Syl. Alg., p. 1136). The 

 present species is not manifestly a member of this group and a dis- 

 cussion of the necessity for Lampriscus is therefore not attempted. 



TRIGONIUM HETEROPORUM (Grunow) Mann 



(Van Heurck, Synopsis, pi. 112, fig. 2.) 



See under Trigonium bicoronatum (Castracane) Mann for a dis- 

 cussion of these species. 



TRIGONIUM INELEGANS (Greville) Mann 



(Schmidt, Atlas, pi. 128, fig. 3.) 



The specimen found agrees exactly with Schmidt's figure, to which 

 Grunow gives the varietal name micropora, but is rather wide from 

 Greville's type illustration (Micro. Journ., 1866, pi. 2, fig. 21). 

 Neither of these should be confused with T. punctatum Brightwell, 

 which they superficially resemble. 



TRIGONIUM INGLORIUM (Greville) Mann 



(Micro. Journ., 1865, pi. 9, fig. 18.) 



This seems to be a strictly Philippine Islands diatom, the type 

 having come from Manila. 



