9 227 
2(rr) — 10 (rr). 
Area: Atlantic Ocean from N. of Iceland to 41° 3., Mediterranean, Red 
Sea, Indian Ocean to 33°S., Malay Archipelago, Pacific Ocean southwards to 8. 
of New Zealand. 
R. alata Btw. var. gracillima (Cl.) Van Heurck, Synopsis, Pl. 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; ER. gracillima Cleve, New Diatoms, K. Sv. 
Vet. Akad. Handl. Bd. 18, 5, 1881, p. 26, Pl. VI, 
f. 78; Phytoplankton p.24; Schréder, Neapel, 
p. 26. 
2(rr) — 4(rr) — 10 (x). 
Area: Most parts of the Atlantic Ocean, Medi- Fig, 3. 
terranean, Red Sea, Gulf of Aden, Malay Archipelago. Phizosolenia alata Btw. 
var. indica (Perag.) Ostf. 
Two cells with different 
directions of the calyptra. 
R. alata Btw. var. indica (Perag.) Ostf. in 
Ostenfeld & Schmidt, Pl]. f. the Red Sea, etc. p. 160; 
RK. indica Peragallo, Monogr. Rhiz. p. 116, Pl. 5, 
f.16; FR. alata v. corpulenta Cleve, Phytoplankton 
p.24, Pl.2, ffl; 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 calyptre, 
showing different directions of the upper part. 
1 (rr) — 2(rr) — 3(rr) — 10(4). 
Area: Tropical and Subtropical Atlantic, Red 
Sea. Gulf of Aden, Indian Ocean, Malay Archipelago, 
Yeddo Bay. 
24. KR. amputata Ostf., n. sp. (sect. Squa- 
mosae Perag.). 
Frustules large, 80—100 » broad; val- 
ves (calyptree) long-conic; squamee 5 in cir- 
cumference; spine transversely cut off, with 
an excavation at the apex and a cavity in 
Fig. 4. 
Rhizosolenia amputata Ostf. 
the lower part. Chromatophores numerous, ee z 
a a whole cell (+), 0 part 
of a cell (A), ¢ the apex 
Allied to R. arafurensis Castr. (Challenger showing the form of the 
Report, p. 74, Pl. 30, f. 12; Peragallo, Monogr. spine (42°), 
15* 
small. 
