KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 27. N:0 3. 187 



mm. Interoostal spaces finely punctate (puncta about 23 in 0,oi mm.), frequently apparently 

 smootli. Lower V- with straight median line, very narrow axial area. Central area transversely 

 dilated. Strise in the middle 18, at the ends mtich closer, about 27 in 0,oi mm. ■ — RhapJioneis 

 Lorenziana Grun. Verh. p. 381. Bhaph. fluminensis GauN. 1. c. Pl IV f. 5. V. H. Syn. Pl. XXXVI 

 f. 34. C. robusta Leud. Fortm. D. de Ceylon I f. 1? Achn. clanica Pant. II Pl. IV f. 66? Bhapho- 

 neis Scutellum Petit D. de Ningpo Pl. III f. 6? 



Marine: Barcelona, Balearic Islands! Adriatic (Grun.), Bab el Mandeb! Macassar Straits 

 (Grove Coll.)! 



This species is in tlie index to the plates in Grunow's monograpli erroneously named R. flu- 

 minensis. I have seen an entire friistule in Grove's coUection, but the coarse structure of the 

 upper valve made the examination of the lower very difficnlt. It is doubtless no RhapJioneis, but 

 a species nearly akin to A. clanica. 



8. A. inammalis Castr. (1886). — EUiptical, apiculate. L. 0,o4.t to 0,o63; B. 0,o2 to 0,o38 

 mm. Upper V. with narrow, linear axial area and slightly radiate costfe (6 in 0,oi mm.) alter- 

 nating with double rows of small puncta, 11 to 14 in 0,oi mm. Lower V. with very narrow axial 

 area. Central area transverse, widening oiitward, and laciniate. Strife 21 (middle) to 25 (ends) in 

 0,01 mm. in the middle alternately longer and shorter, finely punctate. — RhapJioneis mammalis 

 Castr. D. Voy. Chall. p. 48 Pl. XXVI f. 3 (upper valve). Stauroneis taJiitiana Castr. 1. c. Pl. XX 

 f. 16 (lower valve)? Stauroneis apiciilata Greg. Ed. N. Phil. J. X (n. s.) 1859 p. 30 Pl. IV f. 8 

 (lower valve)? Stauroneis? ohesa Grev. T. Bot. Soc. V. VIII p. 237 Pl. III f. 12 (lower valve)? 

 A. mammalis Icon. n. Pl. III f. 13, 14, 15. 



Marine: Galapagos Islands! Macassar Straits (Grove Coll.)! 



Var. reticulata Cl. — Upper V. without rows of puncta between the costee, but connected 

 by longitudinal costse, forming an irregular reticulum. — Pl. III f. 16. 



Marine: Macassar Straits (Grove Coll.)! Galapagos Islands! 



Of the var. reticulata I have seen, besides upper valves, an entire frustule, with distinct 

 median line and transverse central area, but the coarse structure of the upper valve prevented 

 the exact examination of the lower valve, which however seems to have the same structure as 

 the type, although that of the upper valves is so different. The outline of both forms is exactly 

 the same. 



9. A. baldjilili Btw. (1859). — Ehomboid. L. 0,o4.ö; B. 0,03 mm. Upper V. with linear 

 axial area and strong radiate costse (7 in 0,oi mm.) without intercostal puncta, and in the middle 

 alternately longer and shorter. Lower V. without axial area, central area small rounded. Stria; 

 10 to 11 in 0,0 1 mm., strongly radiate throughout, punctate, in the middle alternately longer and 

 shorter. — Odontidium Bald. Btw. M. J. VII p. 180 Pl. IX f. 10. RJiapJioneis Raid. Grun. Verh. 

 1862 p. 379. AcJm. bald. Grun. A. D. p. 21. Pant. III Pl. XIII f. 204. Icon. n. Pl. III f. 4, 5. 

 A. bald. var. subquadrata Pant. III Pl. XIII f. 202. Dimeregramma baldj. Walker and Chase 

 N. E. D, Pl. I f. 3; 1886. 



Marine: Baldjik near Varna, fossil! 



Microneis Cl. N. G. 



Valves small, linear to lanceolate, not very dissimilar. Upper valve with iine, parallel 

 strise and central, straight, narrow axial area. Lower valve with fine, almost parallel striee. No 

 marginal rim. Frustule genuflexed. 



This group comprises a number of usually very small diatoms, partly stipitate, partly free 

 and frequently genuflexed. Most of them inhabit fresh water, hot springs and brackish water. 

 As to their affinities, they seem to be most nearly akin to the Nainculce minuscula and Naviculce 

 mesoleice. 



