316 CONTRIBUTIONS PROM Mil NATIONAL HERBARIUM. 



for the separation by Schmidt of his P. inJL ra There is but little doubt of /'. robutta 

 belonging here; the Blight difference in beading amounts to nothing, .1- this b] 

 i- most variable in that respect, and the lighter and more curved Bepta app< ar to me 

 uiiiin; I have, however, followed this synonym with a question mark. 



Pound at station 2807, Galapagos I -land.-. 



HEMIDISCUS Wall. 



Hemidiscus Wall. Trans Micr. Soc. Lond. n. s. 8: I2.pl. ../'•■ f.1860. Pritch. Hist 



[nfiis. ed. 852. L861. 

 / dia Bail.; Pritch. Hist. [nfus. ed. 1. 852. 1861. Rabh. Fl. Eur Ug. 1: 317. 



L864 I astr. Rep. Voy. Chall. Bot. 2: 1 1^ 1886. Van Heur. Treat 1m. ,1 



1896 De Toni, Byll. Alg. 2: L324. L894. II. I.. Smith, The l.« as 1: mi'. 

 j Ehrenb. PhyB. Abh. Akad. Wise. Berl. 1861: 294. L862; 1872: 



1*1. ■>. 1. 8. 1873. 

 Palmeria Grev.; * ;r.\ . Aim. Mag. Nat. Hist. III. 16: /</. :,. /. 1 .. L865. Van 



Heur. Treat. Diat. 538./ 186. L896. II. I.. Smith, Sp. Diat. Typ. no. :'> s 7. 1874. 

 othecium Ehrenb. Afikrog. pi ... XVIII. f. \. 1854, in part. Griff. A Henf. 



Micr. Diet -1. :;. 347. pi :.'./. is. is::,. 

 Most diatomists have retained the name Euodia Bailey, notwithstanding the fad 

 ilia 1 Hemidiscus of Wallich is a year older. Besides this objection t<> the name there 

 is a still Btronger one in the fact thai the name Euodia was used by florster in L776 

 fora genus of flowering plant- of the family Rutaceae. That Euodia Bailey and Hemi- 

 discus Wall, an- synonymous i> certain, tin- only mark of distinction being the peeu- 

 donodule observed mar tin- ventral margin of the valve by Wallich. As Kali- remarks, 

 this may have been overlooked by Bailey; or, as is more Likely, ii was absent from his 

 specimen. It is uot infrequent t" find the Bame forms with or without tin- peeudo- 

 aodule, or to find a complete frustule with one valve bearing a pseudonodule ami the 

 other lacking it. It is also impossible to hold Greville's Palmeria a- a Beparate genus. 

 Tin' indefinite hyaline central area is the only real difference ii possesses, a charac- 

 teristic too trivial i" warrant its separation, a- on tin- -aim- basis we should have to 

 divide many other genera, Buch a- Coscinodiscus. The other quality claimed for 

 Palmeria, namely, fine submarginal spines, with lines from these running radially to 

 the center, is not at all peculiar to Greville's specimen. Wallich refers to the mar- 

 ginal processes as "marginal puncta" ami figures them on the dorsal side A careful 

 examination of Greville's Palmeria in the excellent specimens of II. 1.. Smith's 

 type slides no. 387 convinces mo it is without the distinctions necessary for separate 

 generic tank: though ii should be classed a- a Beparate Bpecies, viz, Hemidiscus hard- 

 manianus (Grev. Mann. 6 On the other hand, it should ho hero noted that the strik- 

 ing build of the members of this genus leads to the too easy conclusion that all 

 cuneiform frustules bearing a reasonably close resemblance to the original Bpecies, 

 Hemidiscus cuneiformis Wall., must be mere varieties of it. Of course such a conclu- 

 sion would he no more justified than to look upon all circular diatoms covered with a 

 delicate, radially arranged network of hexagons as varieties of Coscinodiscus radiatus 

 Ehrenb. I have, therefore, below given to two specimens found by me the separate 

 specific name- bestowed by < lastracane, although their general similarity to Wallich's 

 original form is apparent. 



Hemidiscus cuneiformis Wall. Trans. Micr. Soc. Lond. u. b. 8: 42. pi. .'. / 



I860. Mool,. Diat.-taf. pi 31. f. S ). L890. Pritch. Hist. [nfus. ed. 1. 853. pi. 6. 

 '. /.;. L861. 



a Pritch. Hist. [nfus. ed. 1. 853. 1861. 



■I'm hardmaniana (Grev I ii. L. Smith; Hab. Cat L32, L877, 



