194 



according to Lägst. W. Sm. B. D. II Pl. XXXVII f. 302. V. H. Syn. p. 129 Pl. XXVI f. 21 to 

 24. A. multiarticulata Ag. Consp. p. 59 (1832). A. capensis KtJTZ. Bac. p. 76 Pl. XXI f. 1 (1844). 

 Achnanfhidium arcticnm Cl. D. Arctic Sea p. 25 Pl. IV f. 22 (1873). Achn. Löczyi Pant. II p. 57 

 Pl. XII f. 217 (1889). 



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

 ((xrun.), Mediterranean Sea! Amsterdam Island (Grun.). 



Var. seriata Ag. (1827). — Frustiiles concatenated into Diatoma-like series. Valves elongated, 

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

 Consp. p. 60. Cymhosira Agardhii KtJTZ. Bac. p. 77 Pl. XX f. 3 (1844). A. ser. var.? cuneata 

 Grdn. a. D. p. 19. A. suhsessilis var. enervis Pbtit Mém. de la Soc. de Cherb. p. 207 Pl. XXIII 

 Pl. III f. 2? 



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



Var. angustata Grbv. (1859). — Elongated, narrow. L. 0,o7 to 0,i5; B. 0,005 to 0, 01 mm. 

 Strige 10 to 15 in 0,oi mm. — A. angustata Gkev. M. J. VII p. 163 Pl. VIII f. 9. A. pcnnata 

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



Marine: Californian guano (Grev.), Ceylon! 



Greville fignres two cohereiit 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 Gkev. (1865). — Frustule biarcuate, long and narrow. Lower valve 

 linear obtuse. L. 0,i.'5; B. O.oi mm. Strise parallel, 12 in 0, 01 mm. punctate, puncta 13 in 0,oi 

 mm. — Achnanthes pemmf. Gkev. 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,o6 to 0,o7.'); 

 B. 0,02 mm. StrifB and puncta 8 to 9 in 0, 01 mm. — Achnanthes indica Brun 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. infläta, 

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

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

 f. 11) and A. hergnelensis 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 striaj of the 

 latter so fine. 



8. 0. perpnsilla Pant. (1889). — V. broadly lanceolate. L. 0,oir>; B. 0,oo8 mm. Lower V. 

 with nari'ow axial area. Central area a nai'row transverse fascia, reaching to the margin. Median 

 line straight. Striaj 17,5 in 0, 01 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 sitbscssi.Jis. 



i). A. siggliitiiiiita Grun. (1880). — V. narrow, lanceolate. L. 0,022 to 0, 028; B. 0,oo4 to 

 O,oiiri mm. Upper V. with 13 i)unctate strite in 0,01 mm. Lower V. witli 15 punctate stria; in 

 0,01 mm. — A. I), p. 19. 



Marine: Triest. 



This, to me unknown form, resembles according to Grunow A. subsessilis, bnt occurs attaehed 

 hy tlif lowfM' valve to seawfods, not on gelatinous stalks as A. ,s?(/j,vr',v.s77/.v. 



i 



