.MANN- DIATOMS OF THE ALBATROSS VOYAGES. 313 



Rabh. I'!. Eur. Alg. 1: 317. L864. Grun. Denkschr. Akad. Wien 48 : 67. L884. 



Truan & Witt, Diat. Bayti 24. L8 

 SoZiumHeib. Km. Overs. DanskeDiat. 22, 52. pi \ i. W. L863. Grun. Denis 



Akad. Wien 48 2 : 69. pl2.J. 61. 1884. DeToni, Syll. Alg. 2:860. L894. Rabh. I'l. 



Eur. Alg. 1: 319. L864. 

 The original genus of Ehrenberg, though practically restored by Van Beurck by 

 the inclusion of the three genera separated from it by II ontained some forms 



that would now be classed elsewhere. Thus //. antarctica Ehrenb. tt is probably a 

 Biddulphia. The grounds advanced by Beiberg for dividing the £ of the most 



trivial character. A- < rrunow points out,6 Trinacria an. I Solium are merely triangular 

 and quadrangular examples of Bemiaulus; while Corinna differs -imply in n< frus- 

 tulee appearing wedge-shaped in /.'-mil view. 1 1 may be added that certain Bpe< 

 Trinacria are indistinguishable from members of the loose genus Triceratium. Tim 

 close relation of all these forms to the genus Biddulphia is evident; a fad strikingly 

 illustrated by comparing Hemiaulus polymorphus Grun. with Biddulphia elegantula 

 Grevj Tin- genus Ploiaria Pant., represented by the single species, /'. . 

 Pani..'/ has greal resemblance to Bemiaulus in the valval view; but whenseenfrom 

 the zonal view its somewhat concavo-convex form and its apices unprotruded ami des- 

 titute of any spines, make ii- union here unnecessary. 

 Heniiaulus polycystinorum Ehrenb. Mikrog. pi. 86. f. 48a d. L854; Ber. Akad. 



Wiss. Berl. 1855: 299. L856; Thy.-. Abh. Akad. Wiss. Berl. 1875: 52. pi. l.f. 



12 15. L876. Grun. Denkschr. Akad. Wien 48 2 : 65. pi. .'./ >. L884. Schmidt, 



Atlas pl.l4S.f. :■■ .">. L889. Pritch. Him. [nfus. ed. L 851. L861. DeToni, Syll. 



Alg. 2: 849. L894. Boyer, Proc. Acad. Phila. 1900: 7 in. L901. 

 Hemiaulus antarcticus Weisse in Witt, Verh. Russ. Minn. Ges. II. 22: 39. pi 



l :. L886, nol Ehrenb. 

 Found at suit ion 4029H, Bering Sea. 



PLOIARIA Pant. 



Plviaria Pant. Beitr. Bacill. Ung. 2: 84. pi. 28. f. L889. De Toni, Syll. Alg. 



2: 860. L894. Van Beur. Treat. Diat. 457./. 186. L896. Boyer, Proc. Acad. Phila. 

 1900: 711. L901. 

 Hemiaulus Ehrenb. in part; Pant. Beitr. Bacill. Ung. 1: 50. pi 

 The separation of this genus from Bemiaulus appears to me justified. The single 

 species at present known differs from any species of Bemiaulus in several respects. 

 In thf zonal view the frustule is strongly concavo-convex and the api< stitute 



of vertical projections tipped with a claw. The center of the valve on one side is 

 raised into a strong dome almost or entirely wanting on the other valve. In the valval 

 view this central area is seen to be unseparated from the rest of the valve by rectangu- 

 lar boundary lines, such as appear in the similar form of Bemiaulus, known . - 

 txeavata Beib. So far as I know, the genus is exclusively fossil, and 1 have hoard of 

 no cases whore the frustulee occur in connected Berres, as they do in Bemiaulus. 

 Ploiaria petasiformis Pant. Beitr. Bacill. (Jng. 2: 84. pi. L889. De 



Toni, Syll. Alg. 2: 860. L894. Van \\>uv. Treat. Diat. 457./ 

 Pro,-. Acad. Phila. 1900: 742. L901. 

 Hemiaulus petasiformis Pant. Beitr. Bacill. [Jng. 1: •"><>. pi 

 Found at station L029H, Bering Si 



Ehrenb. Mikrog. pi. 85 A. XXI.f. tS ... XXII. f. 15 L854. 

 nkschr. Akad. Wien 48 : 60. L884. 

 ■ Schmidt, Atlas pi . and pi. 119. f. 10. 



Pant. Beitr. Bacill. (Jng. 2: B4. pi. - 



