312 CONTRIBUTIONS FROM THE NATIONAL HKHBATiTUM. 



Diatoma D C, in part; Lyngb. Hydro. Dan. 181. 1819. C. Ag. Kyst. Alg. (J. 1S2I. 

 Dlddulphla S. F. Gray, Nat. Arr. 1; 294, 1821, in pari. 



Isthvtu'llu Clcve, Bill. Sv. Vot. Akad. Ilandl. 1'^: 10. 1S73. Tiv Tuni, Syll. Alg. 2: 

 834. 1894. 



The rcwtrirtion of the aT>ovo genus by Cleve (see above) to the single species, /. obli- 

 qiiaia (J. E. Smith.) Ehrenb., (/. nervosa Kiitz.) and the forminj^^ of a new genus, 

 IpthmieUu, lo inehi(h^ the spoei(\s<k\stitnte of ribl)ing is wholly imwarraiitedj and has 

 been followed by no one but Do Toni in his Sylloge Algariun. 



Isthmia obliquata (J, E. Sniilli.) Elircuib. Infus. 209- /)/. 16,/, 5. 1838. Ralfs, Ann, 



Mag. Xat. lli.st. 12: 272. pJ. S.f. 2. 1843, 

 lathmia nervom Kiitz. I5aeilh 137. pi. 19. J. 5. 1844. W. Smith, Synop. Brit. Diat. 



2: 52. j)l 47. 185ii. Rabh. Ih^tr. 1: D. pL 4- f- 12. 1863. O'Meara, Troc. Roy. 



Irish Aoad, II. 2: 271). j)L 27. f. 15. 1875. 11. L. Smith, Sp. Dial. Typ. no.20(K 



]S74. Schmidt, Alias p^ 1S5,f. 1-ii. 1888. Priteh. Hist. lufns. e<l. 4. 851. 18()I. 



Van Ileiir, Treat. Diat. -^J52. pi 34- f- 891, 1861. Grun. in Fenzl, Reise Novara 



Bol. 1: 102. pi lA.J. 21. 1870. 

 Conferia obliquata .] . E. SuiiLli, Eng. Rat, 26: pi 18G9. ISOS, in part. 

 Dialottia ohllquaiuvi Lyng. Hydro. Dan. pi. 62. 1819, in pari. C. Ag. Consp. Diat* 

 55. 1832, 



■ 



Isthmia obliquata C. Ag. Consp. Diat. 55. 1832, in part. Kiitz. Linnaea 8: 579. pi 4- 

 /. olK 1833. 



Ehr<*nb<Tg« was 1h(^ Hrst to separate the then single species of Lsthniia into two, to 

 the lirst of whioh, corr<^sp(»nding to what Kiitzing subseqiu^ntly <alled /. nervosa^ he 

 gave the original specific nanu^ obliquata. l> To the second he gave the name enervis,^ 

 The name ohliquafa^ thongh recognized by some writ(Ts/^ was generally dropped in 

 favor of the more descriptive name of Kiitzing. Boyer, in atlempting to reinstate 

 obliquata, has done so at the expense of Ehrenberg's ourvis, an arrangement quite 

 impossible in view of Ehrenberg's descriptions and figures, Kutzing*s nervoaa not 

 having been i)roposed until 1814. e 



It is renuirkable how few specimens of this common marine diatom were met wiih in 

 the dredgings and soun(Ungs examined for this report, especially as, on account of its 

 large size aiKl massive structure, it could not have been overlooked. 



Found at stations 2844, 2848^ 2851, 3200II, 4013H, 4530H, south of Alaska peninsula, 

 off southern California and Honshu Island, Japan. 



HEMIAULUS Ehrenb. 



TTemiaaht:^ Ehrenb. Ber. Akad. Wiss. lh>rl. 1844: 199, 203. 1845; Mikn.g, pi SGj. 4S 



Char. eui(m<l. lleib. Krit. Overs. Danske Diat. 22,43. 1803. Grev. Trans, Micr. 



Soc. Lend. n. s. 13: 27. pi S.f. 5-16. 1865. De Toni, Syll. Alg. 2: 836. 1892. 



Van Hour, Treat, Diat. 455. /. 182-185. 1896. Cf. II. L. Smith, The Lens 1:89. 



1872. and (Srun. D(nikschr, Akad.AVien 48-^: 60. 1884. Boyer, Broc. Acad. Pliila. 



1900: 738. J 901. 

 Comma lleib. Krit. Overs. Dansko Diat. 22, 53. pi S.f. 8. 1863. 

 Trinacria lleib. Krit. Overs. Dauskc^ Diat. 22, 50. pi S.f. 7. 1SC3. Witt, Verb. Russ. 



Min. Ges. II. 22: 34. jd. 11. f. 1 11. 1886. De Toni, Syll. Alg. 2: 854. 1894. 



a Ehrenb. Infus. 209. 1838. 



?>0p. eit. ;)?. IG.f. 5. 



cOp. cit. pi 16. f. 6. 



d Ralfs, Ann. Mag. Xat. Hist. 12: 272. 1843. Lag(Tst. l*.ih. Sv. Vet. Akad. llandl. 

 1^*; 16. 1873. 

 , ^ Cf. Boyer, Proc. Acad. Bhila. 1900: CSS, GS9. 190L 



