MAN^^ 



■DIATOMS OF THE ALBATROSS VOYAGES. 



351 



wide variety of that species. But Grunow's form is in no sense Schmidt's diatom. 

 Aside from a general similarity of outline and of the median line area, they are most 

 strongly contrasted. Not oidy does it fail to agree in beading and the direcLi(tn of the 

 striae, ewpeeially at the center, willi the figin-e in the Alias quoted by Gr\nut\v,«' but 

 if we take Schmidt's original type form i' the difference is even more pronounced. 

 Grunow also includes what Lag(*rstc(lt has perhaps (^roneously called N. didyma 

 (Ehnmb.) KOtz.c This form, the author says in a not(% is close to one of Donkin's 

 figures of i\^ didyma,^ But without going into (he merits of Lagerstxnll's iduntirioa- 

 tion it is enough to say that it has little if any resemblaiu'<^ to either Schmidt's suh- 

 cbuia or t<t my species, and that snhvincia is far closer to DoTikin's figurt- (>f didyma 

 than the one givc^n by Lagerstedt, a fact noted under A^. f^nhrincta in this mport. The 

 exact type form of Schmidt's X. sffbclncta occur? at station 3008II, furresponding 

 with it in form, markings, and size. \\'h( n it is compared with Ihi.i species, all (rue 

 resemblance vanishes. It may be instructive to add \wyv the measurements of Gru- 

 nowV and Schmidt's specimens for comparison with those given above. Length of 

 Grun<iw's largest specimen, 0.107 nun.; smallest, 0.002 mm; of Schmidt's type, N. skL- 

 cimia^ 0.054 mm. 



Type in the U. S. National Museum, No, 590148, from station 3604, Bering Sea, 



August 12, 1895; 1,401 fathoms, botton; of gr(>en ooze. 



Navicula pleurostaurum Mann. 

 Slaaroneis acuta W. S. Smith, f 



/• 



1853. Pritrh. llist. Infup. od. 4. 914. pi 7./. 76. 1801. Van llcur. Syr.op. 68. 



/■ 



Dial. 159. pi. l.f. 51. 1890. Gnin. Denkscliv. Akacl. 



Wii-n 48-: 47. 1884. II. L. Smith, Sp. Diat. Typ. no. 485. 1874. \\\A\v, Diat. 



N. A. pi. 8.f. It. 1800. Schmidt, Atla.s pi. 141. f. 4-5. 1889. Dehy, Ann. Soc. 



Makcol. Bclg. 11: 88. 1876. Cleve, Sv. Vet. Akad. Hand!. 26-': 150. 1894. 

 PUu roaiaurum acuiti//t. Ilabh. Iledwi^ial: 17. pi. l.f. B. 1859. Jan. in Hfdwigia 



1: 25. 1859; 5: pi. S.f. 1 S. 1863. Ral)h. Fl. Eur. Alg. 1: 20. 259./. C. 1864. 

 Plcnwstauron aciihim Kal)h.; De Toni, Syll. Alg. 2: 222. 1891. 

 fHaiirovrh Icochii Pant, l'><>itr. Par-ill. Ung. 3: pi. G.J. 1)3. 1893. 



Ap I find it nof't'ssary to di.'icard llic giMUiw Staui'Dni'iss as s(>parate from Navirtda for 

 reasons already given, I am compelled to give a new sj)e(afif name to this well-known 

 diatom. The nam<^ N. acuta is pr(HMni)t(Ml l)y N. acula Kiitz., an indeterminate form^^ 

 as w(41 as N. acuta (W. iSmith) O'Meara./ 



Th<^ synonymous form Stauroneu kovhii Pant, ean not he used, as there is a iV. Jcochii 

 Pant.iy I therefore apply to this diatom ihe specific name plfurostaurum, taking the 

 lapsed generic name of Ral.)enhorst,^of which this partieuhir diatom waa the type. As 

 Ilabenhorst has pointed out, this diatom is peculiar in the sunken stauros as well as in 

 the internal tlii(;kening of the side margins, especially toward the ends, which give a 

 thickened, hooded aspect to the apices. De Toni and others accept this as an ade- 

 quate generic distinction. I do not consider this and similar forms, as N. {Slaaroneis) 

 falmen liright,, to be sufficiently distinct from other examples of Navicula to require 

 their separation. Tleve, i while retaining this in Stauroueis, makes use of Pleuro- 



« Schmidt, Atlas -pi. IS.f. 41- 1875. 



?> Jahresb. Komm. Deut. Meere 2; pL 2.f. 7. 3874. 



cBih. Sv. Vet. Akad. llandl. 3''- 36. pi. l.f. 4. 1S7<). 



dBonk, Brit. Diat. pi l.f, 8h. lS71-7:i. 



cKutz. liacill. 93. pi. 3.f. 69. 1844. 



/ Proc. Roy. Iri^h Acad. 11. 2: 407. pL 34. f. 5. 1875. 



gTm\L Beitr. Bacill. Ung. 2: 49. pJ. 4j^ "72. 1889. 



^Hedwigia 1: 17. 1«859. 



iSv. Vet. Akad. Ilandl. 26': 150. 1894. 



