290 CONTRIBUTIONS PROM Till NATIONAL HERBARIUM. 



-ha i on i- as those in the following specie* which are in striking contrast to the Biddul- 

 phia idea, [therefore make use of Cleve's genus, excluding those triangular forma 

 thai have definite central areas distinctly different in sculpture from the rest of the 

 valve, represented by the genus Entogonia, and including forme having four or more 

 angles Nothoceratium D< Toni agrees in pan with this, except for tin- limitation 

 of ill-- species to th i or more angles, an utterly impracticable provision 



leading to the absurd distinction between the four-sided and 1 1 1 * - six-sided speci- 

 mens of / " atiun paralleh i the former of which he places in the genus 

 Amphitetras and the latter in Nothoceratium. 



Trigonium altemans Bail Mann. 



eratium all Bail. Smithson. Contr. Knowl. 2*: 11. pi. /. l s ">!: 



2"*: Hi. L851. Bright. Quart. Jourh. Mm. Sci 1: 251. pi :./. 19a i>. Is.".:;. Jan. 



Abh. Schles. Gee. Vaterl. Cult. 1862*: 15. pi. 1 A./. 16. 1862. W. Smith. Synop. 



Brit. Dial. 1: 26. pi 5./ ',■>. pi 30. / \5. L863. Schmidt, Atlas pi. 



(not/ 19 ". T. campeckianum Grun.). L882. O-'Meara, Proc. Roja Irish.Acad. 



II. 2: 278. pi 27./. /.'. L875. Van Beur. Synop. pi 11 H Pritch. 



Bist. [nfus. ed. 4. 854. pi 6./ :i. L861. Moeb. Dial -taf. pi l.f. 19a b. L890. 



Wolle, Diat. N. A. pi 100./. 16, 18(noi j>J. t06.f. I. L890. DeToni, Syll. Alg. 2: 



941. L894. 

 Biddulphia alternant Van Beur. Synop. 208. L881. Boyer, Proc. Acad. Phila. 



1900: 719. L901. 

 Triceratium variabih Bright. Quart. Journ. Micr. Bci. 4: 275. pi 17./. 19a-c. L856. 



Moeb. Diat.-taf. pi. 9./. 19a c. L890. West, Trans. Micr. Soc. Lond. n. b. 8: L49. 



pi. ;./. 7. I860. Pritch. Bist. [nfus. ed. i. 854. L861. Leud. Fort.-Mem. Soc. 



Emul. St. Brieuc 60. h 

 There is a specious resemblance here to the Biddulphia type in the slighl elevation 

 of the angles and this is intensified by their being apparently cul off from the rest of 

 the valve by definite internal Bepta. This is especially so if several of the figures above 

 cited are relied on instead of the diatoms themselves. That there arc qo proc - 

 the angles can be seen by a careful examination of more than one specimen of this 

 species. Sometimes the extremities of the angles are not raised at all above tl 

 of the valve and in some cases they are Blightly lower. The lines usually (not always) 

 marking off the extremities and making them resemble Biddulphia processes have 

 no significance; for in the forms classed by Brightwell, as T. variabile, the valves 

 are penetrated by numerous false septa extending inward from the margin. The 

 angles are often beaded exactly like the rest of the valve. Altogether these angular 

 portions are voy different from the true processes of Biddulphia. D may be men- 

 tioned in this connection that the frustules are not joined by alternate angles into ■ 

 zigzag chain, as is common in Biddulphia, but when united, which is rare, it is face to 

 face; hut it should also be said that too much significance should not be placed on this 

 fact . either here or elsewhere. Schmidt, De Toni, and ether- do not admit thisspeciei 

 into Biddulphia, but retain it in Triceratium. 

 Found at Btation 3696, off Bonshu Island. Japan. 



Txigonium articum (Bright.) Cleve, Ofv. Kgl. Vet. Akad. 24: 663. L868; Sv. Vet 

 Akad. Bandl. 1 : 8. L873. 



atium arcticum Bright. Quart. Journ. Micr. Sci. 1: 250. pi 4- / tl. I s "'-"- 

 Moeb. Diat.-taf. pi /./. 11. L890. Grun. in Fenzl, Reise Novara Bot. 1: 24. 1870. 

 Di Toni, Syll. Alg. 2: 920. L894. Pritch. Bist. [nfus. ed. l. 856. 1861. Cl< 

 Grun. Sv. Vet. Akad. Bandl. 17': L5, III. 1880. Schmidt, Atlas pi 76. J 

 pi 3,10 M.1882; pi. 81./. 4. 1885. B. L. Smith, Sp. Diat. Typ. no. 



1874. Van Beur. Synop. pi lit./. 1. 1881. 

 Biddulphia arctica Boyer, Proc. Acad. Phila. 1900: 714. 1901. 



"Tr.iie. Micr. Soc. Lond. n. b. 13: 104. pi 9./ ! 



