194 p. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



according to Lagst. W. Sm. B. D. K PI. XXXVII f. 302. V. H. Syn. p. 129 PI. XXVI f. 21 to 

 24. A. mulHmiimlaia Ag. Con.sp. p.' 59 (1832). A. capensis KtJTZ. Bac. p. 76 PI. XXI f. 1(1844). 

 Achnanthidiuni arcticnm Cl. D. Arctic Sea p. 25 PL IV f. 22 (1873). Achn. Loczyi Pant. II p. 57 

 PL XII f. 217 (1889). 



Brackish and marine: Finmark! Coasts of Britain (Sm.), North Sea! Baltic! Caspian Sea 

 (G-rnn.), Mediterranean Sea! Amsterdam Island (Grun.). 



Var. seriata Ag. (1827). — Frustules concatenated into 13iatoma-like series. Valves elongated, 

 narrow, frequently broader at one end than at the other. — A. seriata Ag. Bot. Zeitung 1827. 

 Consp. p. fiO. Gymhosira Agardliii Kutz. Bac. p. 77 PL XX f. 3 (1844). A. ser. var.? cuneata 

 G-RUN. A. D. p. 19. A. subsessilis var. enervis Petit Mem. de la Soc. de Cherb. p. 207 PL XXIII 

 PL III f. 2? 



Marine: Adriatic (Kutz), Java! Labuan! Pacific Ocean (Grun.). 



Var. angustata Grev. (1859). — Elongated, narrow. L. 0,o7 to 0,i5; B. 0,oo5 to 0,oi mm. 

 Striffi 10 to 15 in 0,oi mm. — A. angustata Grev. M. J. VII p. 163 PL VIII f. 9. A. pennafa 

 Cl. Vega p. 504 PL XXXV f. 2. 



Marine: Californian guano (Grev.), Ceylon! 



Grevillb figures two coherent frustules in the zonal view, for which reason the identifi- 

 catation with A. pennata Cl., the figure of which represents a lower valve, is somewhat doubtful. 



Var.? pennceformis Grev. (1865). — Frustule biarcuate, long and narrow. Lower valve 

 linear obtuse. L. 0,i5; B. 0,oi mm. Striae parallel, 12 in 0,oi mm. punctate, puncta 13 in 0,oi 

 mm. — Achnanthes penncef. Grev. T. Bot. Soc. Edinb. Vol. VIII p. 438 PL VI f. 11 to 13. 



Marine: Sandwich Islands! 



Var. indica Brun (1893). — Centrally constricted, with cuneate ends. L. 0,06 to 0,075; 

 B. 0,02 mm. Strise and puncta 8 to 9 in 0,oi mm. — Achnanthes indica-^Bxm Diatomiste I 

 p. 173 PL XXIV f. 14. 



Marine: Rodriguez (Brun). 



A. brevipes is an exceedingly variable species, on the varieties of which a great number of 

 »new species», usually imperfectly described and figured, has been founded. The characteristics, 

 by which these reputed species differ, are such trifling ones as the shape of the valve, the size of 

 the stipes, the excentricity of the axial area of the upper valve, etc. But as all these characteri- 

 stics are very variable, I am unable to separate as species the above named varieties. A. inflata, 

 A. crenulata and A. coarctata. are so nearly allied to A. brevipes that it is difficult to state any 

 stable characteristics for their distinction. Achn. parallela Castr. (Voy. Challenger p. 41 PL XIX 

 f. 11) and A. herguelensis Castr. (1. c. PL XX f. 41) would seem to belong to the varieties of 

 A. brevipes, were not the area of the upper valves represented as central, and the striae of the 

 latter so fine. 



8. C. perpusilla Pant. (1889). — V. broadly lanceolate. L. 0,015; B. 0,oo8 mm. Lower V. 

 with narrow axial area. Central area a narrow transverse fascia, reaching to the margin. Median 

 line straight. Strise 17,5 in 0,oi mm. punctate, slightly radiate throughout. Upper V.? — 

 Pant. II p. 58 PL IV f. 73. 



Marine: Hungary, fossil (Pant.). 



A small form, unknown to me, resembling a small variety of Achnanthes subsessilis. 



9. A. aggluthiata Grun. (1880). — V. narrow, lanceolate. L. 0,022 to 0,o28; B. 0,oo4 to 

 0,005 mm. Upper V. with 13 punctate strise in 0,oi mm. Lower V. with 15 punctate striiB in 

 0,01 mm. — A. D. p. 19. 



Marine: Triest. 



This, to me unknown form, resembles according to Griinow A. subsessilis, but occurs attached 

 by the lower valve to seaweeds, not on gelatinous stalks as A. subsessilis. 



