r 



MAXX^DTATOMS OF THE ALBATKOSS VOYAGES, 297 



dkvs separating tlio valves make theiu clearly deservin^^ of a separate generic rank. 

 A reference is nuule by li. W. Bailey to these forms liaviiig been recorded by his fatlicr 

 under the generic nani(^ Gryniaia, which has never been publi^^hed except aw a 

 synoniyni. Van Heurck spells this genus Dityhim in hi.s text, but Ditylium in his 

 phites. De Toni spells it Ditylium and .^ays in a note— ''NonnulU auctores scribuut 

 Dityluni^ ex. gr. clarus A^an Heurck." I prefer to retain the original spelHng as above. 



Ditylum sol (Van Ileur.) De Toni, fiyll. Alg. 2: 1018. 1894. 



Tnixraiium (Diiylium) sol Van Ileur. Synop. pi 115. / 1-2. 1881. Schmidt, Atlas 

 pi. 152. f. 4-9. 1890. 



There is a close similarity in all th(^ forms of Dilylnm that gives ground for the sus- 

 picion that they may eventually be found to be varieties of one sp<vios. 

 Found at station 4505II, Santa (Vuz Light-House^, Monterey Bay, Cal. 



Ditylum undulatum (Briglit,) Mann. 



Triccndium undulatum Bright. Quart. Journ. Micr. Sci, 6: 154. pi. S.f. 1-5, 8, 1858. 

 Cleve, Bih. Sv. Vet. Akad. Ilandl. l^^: 6. IS?."?, Cleve, Bih. Sv. Vet. Akad. 

 Handl. 5«: 17. 1878. 



Triceratium imdalatuni Ehrenb.; Schmidt, Atlas pL 151, f. 41. 1890. Pant. Beitr. 



Bacill. Ung. 1: pj, 18. f. 164. 188(5. 

 Triceratium. nndulatuvi V\\ Smith; Bewis, Proc. Acad. Phila. 1861: G5. 1862. 

 Triceratiuvi (Dihjlmm) chrenbcrghi Grun.; Van Ileur. Synop. jjL 115. f. 7-8. 18SL 



Walk. & Chaye, Xotes on Diut. 2: 5. pi 4 J- 12. 1887. 

 Triceratium intricalwn \A'est, Tv\xm. Micr. Soc. Bond. n. s. 8: 149. jd. 7./. 5a-b. 1860. 



Van Ileur. Synop. pi 114- f^ 2, 1881. 

 DUijlui/i Intricaiutti Gnin.; Van Ileur. Synop. Idi]. 1885. 

 Triveralium hrigldwelUi West, Trans. Micr. Soc. l^ond. n. s, 8: 149 (pL 7. / 6\ 



doubtful). 18G0. Van Heur. Synop. pi 114-/. S-O, 188B 

 Ditylum trigonum Bail. Bost. Journ. Nat. Hist. 7: 832. pi 7.f. 6, 10, 11. 1861. H. L. 



Smith, Sp. Diat. Typ. no. 142. 1874. 

 IHttjlum inacqualc Baih Bost. Juurn. Xat. Hist. 7: 3.32. pi 7./ 12-14. 1861. 



Tuffen West in In's discussion of Briglitweirs forms ccmfuses matt(?rs considerably. 

 He divides the latter's T. undulatum into two sp(H'i(^s, T. iniricatimi and T. bright- 

 wellii. He speaks of the form he trails T. brightudlii as having inflated margins and 

 refers to Brightweirs figure, whieli shows that characteristic; yet in Ids own figure 

 6a he fails to show that margin. Or, if by '-margin" he" means outhne, the con- 

 vexity he shows in his figure is lacking in the figure he mentions in BrightwelPs 

 plate, I take it that both of AVest's forms are only varieties of BrightwelPs species. 



Ehrenberg's Discoplea undulata ^^ prol>ably does not belong here; but rather is allied 

 to Triceratium radiatum. Bright., a specic^s distinct from ijiis. It is also uncertain if his 

 sp(^<-imen from the so-called ^^Bernuuhi earth," referred to t) as TriccraHum undulatum 

 is this species. It more probably is his Discoplea u nduJata. This Ralfs also looks upon 

 as distinct from the present species, lie says ^ that it is probably identical Avith T. 

 axnatum Kitt, (MSS.)? and that its nearly orbicular outline and (Tenatt^ margin 'Mis- 

 tinguisli it from T. bnyhluxUii.'' On these grounds ahjne it could, however, liardly be 

 St) distinguished. Thore isnoquestion that what Sclimidt calls T, undulatum. Ehrenb/^ 

 belongs here. 



Found at station 4021)11, Bering Sea. 



« Ehrenb. Mikrog. /;/. 3S. XYTTLf. 3. 1854. 

 ^Ber. Akad. Wiss, lierl. 1844: 273. 1845, 

 c rritcli. Hist. Ijifus. ed. 4. 939. ISOl. 

 d Schmidt, Atlas pi 151. f, 41 • 1890. 



