412 Kryptogamen. — Algen. 



apices; median liue very excentric, somewhat arcuate, central nodule transversely dilated. 

 Striae distinctly punctate, transveise, reaching median line, 11 in .01 mm. L. .075. B. .028 mm. 

 Virgin Islands, Canipeche Bay (Gr.) Colon Kitton. 



N. (Alloioneis) Antillarnm Cl. et Gr. V. elliptic, oblong median line a little ex- 

 centric and curved. Striae composed of large distinct puncta, arranged in somewhat irre- 

 gularly decussating oblique lines. The Striae on one side of the valve nearly reaching the 

 median line, leaving only a small area round the central nodule, on the other side the Striae 

 are much shorter, leaving a semi-lanceolate blanc space. L. .12 mm. St. Bartholomew, 

 Golf of Mexico. 



N. (Alloioneis) Kurzii Gr. V. broad, lanceolate, median liue excentric, curved, 

 surrounded by an excentric blaue space, which is irregularly enlarged in the middle and 

 becomes narrower at the ends. The rest of the valve is covered with grauules like those 

 of N. aspera, forming decussating, oblique lines and more narrow trausverse ones 10 — 11 in 

 .01 mm. The transverse Striae reach as far as the median line, if seen under a high power 

 L. .09 — .105, B. .036 mm. Mangrove Swamp, Elephant Point, East Indies. 



N. (Alloioneis) curvinervia Gr. V. oblong or lanceolate, with obtuse ends, median 

 line excentric. Striae (costae ?) sligthly radiating, not reaching the median line, interrupted by 

 two Sharp longitudinal bends of the valve, smooth (under a very high power and favourable 

 light, delicately punctate) 8-9 in .01 mm. L. .068—115, B. .022— .028 mm. Ebendaher, 



Rhoicosigma Antillarnm Cl. Median line sigmoid very elevated on the one half of 

 the valve where is forms a crest impressed on the other half. Striae distinct, transverse, 

 14—15 in .01 mm. L. .425 mm. Virgin Islands. 



Plagiogramma (decussatum var. ?) Antillarum Cl. V. elliptic, extremities broadly 

 rounded; iuterior septa 4, 2 near the ends, 2 near the centre; puncta in transverse and 

 longitudinal rows, trausverse 8—9 in .01 mm. L. .07— .08 mm. Virgin Islands. 



P. carihaeum Cl. Outline resembling P. lyratum Grev. Iuterior septa 4, 2 near the 

 ends 2 in the middle. The two central septa are connected with the endsepta by a streng 

 median rib and by two others following the margin of the valve. Puncta or granules 

 arranged in distinct parallel transverse rows, 8—9 in .01 mm. L. .012— .088 mm. Virgin Islands. 



P. attenuatum Cl. V. small, lanceolate, acute, ends slightly rounded. Septa 2 

 central and near the ends. The two central septa form in the middle a rounded quadran- 

 gular annulus; puncta arranged in parallel trausverse lines 10 in .01 mm. L. .05 mm. St. 

 Bartholomew. 



Nitsschia (Sicjma var.?) valida Cl. et Grün. V. slender alraost straight, sometimes 

 more or less sigmoid, with cuneate ends. Puncta about 4 in .01 mm. Striae distinct 18 in 

 .01 mm. Virgin Islands, Campecln' Bay Gr. Sulu arcbipelago Kitt. 



N. (Jelineckii var.?) acuta Cl. Differ from N. Jelincckii by the cuneate and 

 pointed ends. The ends are connected by a very sharp and visible keel. Striae distinct 11 

 in .01 mm. Virgin Islands. 



N. (lomjissima var.?) curvirostris Gr. Differs only N. lonyissima from by the 

 horns being curved in the samo direction and from N. ventricosa by the fiueness of the 

 Striae; the curvature is of no distinctive value; in mounting N. ventricosa the horns may 

 be placed in any position (K.). St. Bartholomew. 



N (Perri/a) Weissßogü (ürun. V. resembling a long and verry narrow boat, with 

 a Sharp keel, smooth or covered with minute, irregularly scattered grauules, which form 

 coherent longitudinal rows only on the keel and near the margin of the valve; the keel is 

 besides niarked by a row of sharp transverse bars, which (as in all other NUzschiae) lie in 

 the intorior side of the valve and are fastened to eacb side of it. L. .155— .32 mm. Cam- 

 peche Bay Gr. Colon Kitt. 



a. suhylahra valves almost smooth. 



ß. sparsa, v. covered with irregularly scattered minute granules. 



y. interrupta keelbars lengthened and interrupted two or three times. Colon. K. 



N. (Perrya) Gründlcri Gr. Resemblcs N. Weinsß<>(jii but the valve seems more 

 excentric and is covered with parallel transverse punctate Striae, 12—14 in .01 mm. The 



