30 Pp. T. CLEVE. PLANKTON COLLECTED BY THE SWEDISH EXPEDITION TO SPITZBERGEN. 
Hexadoras borealis Cu. N. sp. 
Primordial shell: irregularly spherical, 0,03 to 0,04 mm. in diameter, with irregular, 
rounded or polygonal pores, 2 to 3 on the radius, and thin bars. Spines six, excep- 
tionally more, strong, with triangular apophyses in the middle. Pl. II, fig. 4 a. 
Outer shell: a rounded or octahedric, more or less intricate net-work of anastomos- 
ing, silicious threads, issuing from the proximal edges of the spines. Spines usually six 
(rarely as in Rhizoplegma 8 to 10) strong, three-sided slightly spirally twisted, with 
elegantly aculeate, winged edges. 
Diam. 0,12 to 0,16 mm. Spines 0,1 mm. Pl. II, fig. 4 3, ¢. 
Deep-sea hauls: 
| Date. Lat. N. Long. Depth. Fq. Pi. 
| 1 Vil | 76°36" | 12°13’ RB. | 500—0 m. r TS 
| 27 vir | 79°58’ | 9°33’ R. | 400—0 >» ’ Cs 
| SIN 71°50’ | 19° 2 E. | 230—0 » ’ s 
Habitat: North Atlantic, between Shetlands and Norway, surface, March 1898 (CL.). 
Litholophus ligurinus Hxx. (L. arcticus Aurtv.). 
Surface: ; Deep-sea hauls: 
| 
Date. | Lat. N.: Long. Temp. Sal. ¥q. Pil. | | Date. | Lat. N. | Long. Depth. Fq. Pl. 
1 | | 
‘ Spend seas : | eee eee : : 
25 vit | 73°18°° 7°30°B.| 534 8489 | > a4 B27 vit] 77°39 |1°18'E.] 100-Om. ' 4 TS 
| 27 vill) 79°58’ | 9°35'B) 4,58 | 34,53 r | oT | | Q@7 vr | 75s’ | Psa EB. | 400-0 >» | > cs | 
29 VIIL| 77°23’ | 10°63’ E| 5,58 35,03 . | we 3 
BL VIIL| 76°27’ | 10°48’ B.) 5.35 35,03 a S 
"31 Vill | 76°12 [12°18 B] 6,26 | 35,15 | + ge 4 
Fabitat: Mediterranean, central Pacific Ocean (HKL.). 
Lithomitra australis (Eap.)? The shell Pl. Il, fig. 5 seems to be the upper joints 
of Eucyrtidium australe Ens. from the South Polar ice (Microg. 35 A XNI, f. 18). It was 
found very rarely in the haul 29—30 VII. Lat. N. 78°13’. Long. W. 2°58’. 2,600—O0 m. 
Fig. 6, Pl. Il represents a nearly related form from the same gathering. 
L. lineata (Ens.). Pl. I, fig. 7. 
Deep-sea hauls: 
Date. Lat. N. Long. Depth. Fq. Pl. 
29—30 VII} 78°13" | 2°58’ W. | 2,600—0 m. . cs 
27 VIN | 79 58’ | 9°35 RE. 400—0 >» r cs 
| Bix | 3s | se em | Seow se Ss 
Habitat: Mediterranean, Atlantic, Indian and Pacific Oceans (HKL.). 
