— 11 — 



26. R. Clerei Ostf., n. sp. (sect. Squamosae Perag.). 



Frustules large, 175 — 200 p broad; squamæ 5 in circumference; 

 spine as in R. styliformis; lines of the connection-surface with two 

 thickened parts for the basal part of the spine; chromatophores 

 numerous, small. 



This interesting species is allied to R. Debyana Perag. It is the only 

 species besides R. styliformis Btw., which includes the peculiar Richelia 

 intracellular is Schmidt (in Ostenfeld & Schmidt, PI. f. the Red Sea, 

 p. 146, f. 2). 



2 (rr) — 5 (rr) - 7 (+) — 10 (rr). 



27. R. cyliiidrus Cleve, Phytoplankton 

 p. 24, PI. 2, f. 12; Atl. Plankt. Organisms 

 p. 341; Schröder, Neapel p. 26; Ostenfeld & 

 Schmidt, Pl. f. the Red Sea, etc. p. 160. 



I have figured two frustules of a form 

 which I regard as R. cylindrus GL, although 

 the annulations are not quite like those 

 figured by Cleve. The chromatophores are 

 small. 



10 (r). 



Area: Tropical Atlantic Ocean, especially 

 in its Western parts, Gulf of Naples, Gulf of Fig. 7. Rhizosolenia ey- 

 Aden. linårus Gl. (—■). 



28. R. formosa Perag., Diat. de Villefranche p. 91, PI. 6, f. 43, 

 Monogr. Rhiz. p. 110, PI. 2, f. 2; Cleve, Pl. f. the Indian Ocean and the 

 Malay Archip. p. 23; Schröder, Neapel p. 25. 



3 (rr). 



Area: Mediterranean, Malay Archipelago. 



29. R. hyalina Ostf. in Ostenfeld & Schmidt, PL f. the Red Sea, 

 p. 160, f . 1 1 ; R. pellucida Cleve, PL f. the Indian Ocean and the Malay 

 Archipelago p. 23 and p. 56, PL 8, f. 4. 



2(r) - 3 (rr) - 10(+). 



Area: Red Sea, Gulf of Aden, Malay Archipelago. 



30. R. imbricata Rtw., Microsc. Journ. 1858, Vol. VI, p. 95, PL 5, 

 f. 6; Cleve, Diat. f. the Sea of Java p. 11; Van Heurck, Synopsis PL 79, 

 f. 5, 6; Peragallo, Monogr. Rhiz. p. 113, PL 5, f. 2, 3; Schröder, Neapel 

 p. 26; Ostenfeld Sc Schmidt, Pl. f. the Red Sea etc. p. 161; Cleve, PL f. 

 the Indian Ocean and the Malay Archip. p. 23; R. striata Grev., Diat. 

 South Pacif. Ill, p. 334, PL 3, f . 4 ; Peragallo, 1. c. p. 114, PL 5, f. 1: 

 Leuduger-Fortmorel 1. c. p. 36. 



