

MANN DIATOMS OF THE ALBATROSS VOYAGES. 311 



Certainly so capa1>lo a (U^linoator of the Diatomaceao as Tuffcn WVst would not figure 

 Shadboll/s species so differently from Bright welFs, in the matter of c(dlulation, if they 

 wore specifically near enough to be united. W(^ can, of course, go only by the figure 

 and description and Ijy the opinions of Greville and Ilalfs; but in the absence of type 

 material to examinoj I considei' it best to drop Shadbolt^s species out of this category 

 and unite the other forms above enumerated under the name given by Greville. 

 Found at station 3698, off Honshu Island, Japan. 



Biddulphia subjuncta Mann. sp. nov. Platk XT.VI, figure 4. 



Valve square, the angles rounded and th(^ sides slightly concave; marking of largo, 

 flat bosses, oval or subsquare, radially arranged from the center, which is without 

 hyaline area; central portion within a circle, onedialf the diameter of the valve, flat, 

 thence the valve slightly conv<^x to the border; the four processes set at the extremity 

 of the rounded angles, bi'oad, nearly sessile^ with heavy investing rings and tipped to an 

 angle of 45^ to th<? surface of the valve; each l>ead i>unctate wuth a strong central dot. 



Width of valve, 0.003 nun. 



Type in the U. S. National Museum, No. 590t40, from station 2808, Galapagos 

 Islands April 4, 1888; 634 fathoms, l>ottorn of coral sand. 



I am compelled to name tliis diatom, but do so reluctantly. It is one of a variable 

 group already including many close species, which will need eventually to be revised 

 and condensed when subsequent intermediate forms are discovered. At such time 

 this species should probabl>' disappear. In general markings it is like Triceratium 

 hiquadraium Jan.,a except for the unimj)ortant difference of a circular instead of a 

 quadrate arrangement of the central portion of the valve, a character made prominent 

 in tJie name given by Janisch. But in addition to the minor differences in marking, 

 the processes at the angles ar(^ very broad and sessile, like those figured in T, elegans 

 Grev.,^ a phase of Greville's species in rather too wid(i contrast to his own represen- 

 tation, c My specimen is, on the whole, nearest to an unnanuHl figure of Schmidt's. f^ 



Biddulphia turgida (Ehrenb.?) W. Smith, Synop. Brit, Diat. 2: 50. pi. 62, / 3S4. 



1856. Roper, Trans. ^Vwy. Soc. Lend. n. s. 7: 17. pi. 2. J. 28. 1859. Van Heur. 



Synop. 206. 1885. Coyer, Proc. Acad. Phila. 1900: 711. 1901, 

 Denilvdla litrgida Ehrenb. Ber. Akad. Wiss. Berl. 1840: 207. 1841? 

 Cerataulus turgtdus Ehrenb. Ber. Akad. Wiss. Berl. 1843: 271. 1844. Bail. 



Smithson, Contr. Knowl. 2"": 39. pL 2.f. 26-27. 1851. Pritch. Hist. Infus. ed. 4. 



84G. pi. 6.f. 9. ISCl. Schmidt, Atlas pi 115 J, 12~U, pi 110,/. 1-3. 1888. Castr. 



Ecp. Voy. ChalL Bot. 2: 101. pi 26, f. 6, 8. 1886. Rabh. Fl. Cur. Alg. 1: 313. 



1864. 



Odonlella twyjidaVan Ileur. Synop. pi 70-1/. 1-2. 1881. DeToni, Syll. Alg. 2: 864. 

 1894. 



The specimens found at statitm 369111 are quite small and wholly destitute of the 

 two long spines. 



Found at stations 3691II, 371211, Okh<jtsk Sea. 



ISTHMIA Ag. 



Islhmia G, Ag. Consp. Biat. 55. 1832. IChrenb. Infus. 208. 1838. Kiitz. Bacill. 137 

 1844. W. Smitli, Synop, Brit. Dial. 2: 51. 1856. Oleve, Bih. Sv. Vet. Akad. 

 Ilandl.l^^: 10. 1873. OWIeara, Proc. Hoy. Irish Acad, II. 2: 279, 1875. Pritch. 

 Hist. Infus. ed. 4. 851. 1861. De Toni, Syll. Alg. 2: 833. 1894. Van llcur. Treat. 

 Diat. 451. / 175, 1890. 



a Schmidt, Atlas pi 98. f. 4. 188G. 



£> Schmidt, Atlas/)?. 99,/. 10-1 L 1886. 



c Trans. Micr. Soc. Lond. n. s, 14: 9. pi 2,//24- 18G6 



f^ Schmidt, Atlas pL 99./, 23, 188G. 



31713— VOL 10, rr 5—07 7 



