266 INTRIBUTION8 PROM llll NATIONAL HERBARIUM. 



Ehrenb Mikrog pi • I 

 oplea atlantica Ehrenb. Mikroj 1854. 



loUlla daUtuiana W. Smith, Bynop. Brit. Diat. 2:87. L856. Rabh. PI. Bur. 

 l : :.: 1864 nol II I. Smith. Sp Dial Typ. no. 102. L8 

 Cyclotella tinensia Ralfa in Pritch. Bist. [nfus. ed i 812. pi. B61. 



lotelia atlantica Ralfa in Pritch. Bist. Infus. ed. i 812. pZ. / ■ ' L861. 

 CycloUlla ambigua Grun. in Cleve. & Grui \ K.i> I Bandl. 17 : L19. pi. ?. 



/*. / L880 De Toni, Syll. Alg. 2: L362. L894. 



Though » h « n • is similarity between this and C. stylorum Bright., I do not think it is 

 Bufficienl to necessitate uniting them, as is done by I >«■ Toni. fl They are held u 

 rate by Ralfs, Schmidt, and Van Beurck. There is no doubt about ( Ehrenb 



Ralls being this Bpecies; though Discoplca tinensia Ehrenb., on which Raits bases his 

 name, is Bomewhal questionable. The same is true of C. dallasiana W. Smith, which 

 from the meager description and the absence of any illustration is rather indefinite. 

 II I. Smith's type no. 102 is a typical C. stylorum Bright., to which, therefore, if the 

 two are to be held separate, it Bhould be referred. 



Pound at stations 2688H, L516H, off California and in < rulf of California. 



Cyclotella stylorum Bright. Quart. Jo urn. Miu. Sci. 8: 96. pi. '../". 16. I860. Van 

 Beur.Synop. pi. 92. /'. I 5. L881 Schmidt, Atlas pi. MS.f.6 8. L896. Pritch 

 Hist. Enfus. ed. I. 813. L861. Moeb. Diat.-taf. pi. 19. f. 16. 1890. 

 Cyclotella dallasiana W. Smith, err. det. II. L. Smith. Sp. Diat. Typ. no. 102. L874. 



As only a Bingle valve was found the identification is somewhat doubtful, for withou' 

 a complete frustule it is nearly impossible to decide between the above Bpecies and 

 similarly constructed vah es of Melosira, as, for example, those of M. subornata Schmidt. 



Pound at station 3263H, Bouth of Aleutian Islands. 



HEMIPTYCHUS Ehrenb. 



Hemiptychus Ehrenb. Ber. Akad. Wise. Berl. 1848: 7. L849. 



Arachnodiscus Bail. Ber. Akad. Wiss. Berl. 1849: 64. 1850; in Wilkes U. S. Explor. 



Exped. 17: 171. L874. De Toni, Syll. Alg. 2: L31 1. L894. 

 Arachnoidiscus Deane; Pritch. Bist. Animalc. ed. 2. 318. L852; Bist. [nfus. ed. 1. 



841. pi. 15. f. 18 11. L861. II. L. Smith. The Lens 1: 19, 93. L872. 

 Arachnoidiscus B&i\.; W. Smith, Synop. Brit. Diat. 1:25. pl.Sl.f. 156. l s ">:'>. Deane, 



Quart. Journ. Micr. Sci. 6: 188. L858. 



The above name must take precedence over Arachnodiscus, which was first pub- 

 lished in L850, Ehrenberg crediting the name to J. W. Bailey, who probably commu- 

 nicated the name in a letter to Ehrenberg, as no trace of it can be Found in Bailey's 

 earlier writings. In L850 Ehrenberg discards the earlier name, in consequence of its 

 prior application to a genus of insects, and adopts the very appropriate and descrip- 

 tive name of Arachnodiscus, which was firsl used in England by II. Deane (spelling it, 

 however, as it is now generally Bpelled, Arachnoidiscus in an unpublished paper read 

 before the Microscopical Society of London on March 17. 1847.* 



Ehrenberg's excuse for abandoning his earlier name. Bemiptychus, is n<>t valid. I 

 think it is both unnecessary and unwise to duplicate names in botany and zoology, 

 and especially bo where the forms are. as with the diatoms, close to the dividing line 

 between the two kingdoms. But in this instance 1 here is no duplication; the'hemip- 

 terous name previously established by Germar in K'.:;< being Bemiptycha, not 



a De Toni, Syll. Alg. 2: 1352. 1894. 

 bQuart. Journ. Micr. Sci. 6: L88. L858. 

 cSilh. Rev, Km. 1833. 



