— 9 — 



2(rr) — 10 (rr). 



Area: Atlantic Ocean from N. of Iceland to 41° S., Mediterranean, Red 

 Sea, Indian Ocean to 33° S., Malay Archipelago, Pacific Ocean southwards to S. 

 of New Zealand. 



R. alata Btw. var. gracillima (Gl.) Van Heurck, Synopsis, PI. 79, f. 8, 

 10; Peragallo, Monogr. Rhiz. p. 115, PL 5, fig. 12; Ostenfeld & Schmidt, 

 PL f. the Red Sea, etc. p. 160; Cleve, PL f. the 

 Red Sea p. 1034; Atl. Plankt. Organisms, p. 342; 

 PL f. the Indian Sea and the Malay Archipelago 

 p. 23 ; R. gracillima Cleve, New Diatoms, K. Sv. 

 Vet. Akad. Handl. Bd. 18, 5. 1881, p. 26, PL VI, 

 f. 78; Phytoplankton p. 24; Schröder, Neapel, 

 p. 26. 



% (fr) — 4(rr) — 10 (r). 



Area: Most parts of the Atlantic Ocean, Medi- 

 terranean, Red Sea, Gulf of Aden, Malay Archipelago. 



Fig. 3. 



Bhizosolenia alata Rtw. 

 var. indica (Perag.) Ostf. 

 Two cells with different 

 directions of the calyptra. 



m. 



R. alata Btw. var. indica (Perag.) Ostf. in 

 Ostenfeld & Schmidt, PL f. the Red Sea, etc. p. 160 ; 

 R. indica Peragallo, Monogr. Rhiz. p. 116, PL 5, 

 f. 16; R. alata v. corpulenta Cleve, Phytoplankton 

 p. 24, PL 2, f. 11; Atl. Plankt. Organisms p. 340; 

 R. corpulenta Cleve, PL of the Ind. Ocean and 

 Malay Archip. p. 22 ; R. quadrijuncta Peragallo, 

 Monogr. Rhiz. p. 116, PL 5, f. 17. 



Certainly the R. indica and R. quadrijuncta 

 of Peragallo belong to the same species and this 

 is further identical with the var. corpulenta of 

 Cleve. I have given two sketchs of the calyptræ, 

 showing different directions of the upper part. 



l(rr) - 2 (rr) — 3 (rr) — 10(+). 



Area: Tropical and Subtropical Atlantic, Red 

 Sea, Gulf of Aden, Indian Ocean, Malay Archipelago, 

 Yeddo Bay. 



24. R. a m pu tat a Ostf., n. sp. (sect. Squa- 

 mosae Perag.). 



Frustules large, 80—100 fi broad; val- 

 ves (calyptræ) long-conic; squamæ 5 in cir- 

 cumference; spine transversely cut off, with 



an excavation at the apex and a cavitv in ü7 • 

 1 1 -i i ™' a i Rhizosoleuia amp 



the lower part. Chromatophores numerous, 



small. 



Fig. 4. 



Allied to R. arafurensis Castr. (Challenger 

 Report, p. 74, PL 30, f. 12; Peragallo, Monogr. 



utata Ostf. 

 r), b part 

 the apex 

 showing the form of the 

 )• 



a a whole cell (- 

 of a cell (-^7^) , c 



spine (— 



