242 CONTRIBUTIONS PROM I ill NATIONAL HERBARIUM. 



b valve; the umbilicus generally not always separated from the real of the 

 valve by an irregular line or suture; -i/<- of the umbilicus varying from ■ men- speck 

 rarely wanting to two-thirds the diameter ol the valve; valves slightly convex to 

 hemispherical; markings, outside of the umbilicus, of delicate beading an 

 in da or curved lines crossing each other obliquely to the radii; radial 



lines, continuous or discontinuous, sometimes proceeding from the umbilicus toward 

 or i" the border, in the latter case dividing the valve into unequal segm ents; border 

 narrow, hyaline; connecting zone narrow, hyaline. 



Podosira axgus (irun. in Schneider, Beitr. Kennt. Kauk. 132. l s 7>. .J<>ur. Roy.Micr. 



2:691. pi. U.J.6. L879. De Toni, Syll. Alg. 2: L364. L894, 

 /'"'.''' Schmidt, Atlas pi. 140./. 6. i ss ' ( . Wblle, Diat. N. A. pi. 69. 



L890. 

 Podotira pacifica ( base in Walk. & Chase, Notes on Diatoms 1: 5. pi. X.J. 5. L886. 



This exquisitely beautiful diatom is a wide departure from the type of this genua. 

 The umbilicus is reduced to an indefinite Mar. which is sometimes wanting. The 

 valve is divided into three definite area.-, like those of Cestodiscus, bul without 

 ! agrees in these particulars with the equally aberrant Podoaira 

 liata O'Meara.fl Both these stand bo much alone that they almost merit 

 tion from this genus, li will, however, be observed that three authors inde- 

 pendently assigned it to the present genus. There is also a close enough lik 

 to Podosira corolla Schmidt, 6 to give Bupport to this identification. 



The species is fairly abundant at station 2920H. I am quite sure that in all the 

 specimens examined the massive bosses ornamenting the central area arc not, as 

 Schmidt claims, thickenings on both Bides of the valve, but are on tin- under con- 

 cave Bide only. The outer of the three bands is also different, being not hyaline 

 but plainly crossed with i wo Bets of lines, diagonal 15 to the radii, as is common in 

 this genus; within this is the band of fine radiating linos, as depicted by Schmidt. 



Pound at stations 2920B and 3008H, California to Hawaiian Islands. 



Podosira stelliger Bail. Mann. 



Hyalodiscu* ttelliger Bail. Smithson. Contr. Knowl. 7: 10. L854. Van Beur. 



Synop. 213. pi. >;../'. /. :. 1881; Treat. Diat. 148./. X73, pi. tt.f.650. L896. De 



Toni, Syll. Alg. 2: L367. 1894. Pritch. Bist. Enfus. ed. 4. 814. 1861. Grun. in 



Fenzl, Reise Novara Bot. 1: 27. 1870. Cleve Bih. Sv. Vet. Akad. Bandl. 1 : 



1. L873. 

 Craspedodiscus? Stella Ehrenb. Afikrog. pi. S5B. IV. f. 11. 1854; Ber. Akad. Wiss. 



Berl. 1854: 238. 1855; Pritch. Bist. Enfus. ed. I. 939. 1861. 

 Podosira maculata W. Smith. Synop. Brit. Diat. 2: 54. pi. 49. f. 3X8. L866. Pritch. 



Bist. Enfus. ed. I. 815. L861. Schmidt, Atlas pi. 139. ./'. ; ./'. ;.' unnamed). 1889. 

 Hyalodiscua stelliger Bail.; Fricke's Verzeich. 1902. JI. I.. Smith, Sp. Diat. Typ. 



no. 120. 1874. Schmidt, Jahresb. Komm. Deut. lieere 2: pi. L874. 



Wolle, Diat. N. A. pi. 69. f. i 5. 1890 (figures poor . 

 Hyalodi8CU8 maculatus Cleve, Bih. Sv. Vet. Akad. Bandl. I 1 : I. Lfi 

 1/ maculata Lagers. Bih. Sv. Vet. Akad. Bandl. 8 15 : 9. pi. X.J. i. 1876. 



The peculiar radiating Lines of this Bpecies, dividing the disk, outside of the umbil- 

 icus into whal Bailey calls "sectorial groups" and its relatively coarse beading define 

 this species well. It. <>\ course, grades somewhat into other species, being like all 

 members of this genus variable. It- umbilicus is generally small. The Cleve A 

 Molhr type uo. 1 bearing this name is very wide of the mark. It has practically no 

 umbilicus but rather a ring, small and obscure, with radial interrupted dashes, like 

 an Actinocyclus; in fad it differs from Actinocyclus inter punctatus (Bright.) rXalfa 



".lonrn. Linn. Soc. Bot. 15: 58. pi. X.J. 9. i s 7'. 

 /'Schmidt, Atlas pi. X40.J. XI, 1 L8£ 





