= B18 = 
Goniodoma Stein. 
19. G. acuminatum Stein, Pl. VII, f. 1—16. 
2(rr) — 3(Qrr) — 4(rr) — S(rr) — 6(r) — 7(r) — 1007). 
Area: Atlantic, Mediterranean, Red Sea, Indian Ocean, Pacific. 
20. G. armatum (Schiitt); G. aceuminatum var. armata Schiitt, Die 
Peridinieen Pl. IX, fig. 32; G. fimbriatum Murray & Whitting, Transactions 
of the Linnean Society of London, 2"4 Ser., Botany, Vol. V, Part 9, 
1899, p. 325, Pl. XXVII, fig. 1 a, b. 
2(rr) — 4 (rr) — 10(rr). 
Area: Atlantic, Red Sea, Indian Ocean, Pacific. 
Diplopsalis Bergh. 
21. D. lenticula Bergh, 1. c. Pl. XVI, fig. 60—62. 
1(4+) — 2(rr) — 3(rr) — 10(4+). 
Area: Atlantic, Mediterranean. Red Sea, Indian Ocean, Pacific. 
22, PD. saecularis Murray & Whitting 1. c. p. 325, Pl. XXVIII, fig. 5 a, b. 
10 (rr). 
Area: Atlantic from a little south of the Azores to the Isthmus of Panama. 
Red Sea, Indian Ocean. 
Ostreopsis Schm. nov. gen. 
Body flattened, oyster-shaped. Apex excentric, marked by a 
narrow, slit-shaped area. Longitudinal girdle small, not proceeding 
to apex, only to be seen on the inferior valve. 3 apical plates 
(one of which being reduced) and 1 antapical plate are present. 
Structure of plates porous. 
Fig. 5. Ostreopsis siamensis Schmidt. Fig.6. Ostreupsis siamensis Schmidt. 
Arrangement of plates in the Another specimen. Arrangement of 
superior valve. plates in the inferior valve. 
