BlHANCx TILL K. SV. VET.-AKAD. HANDL. BAND 1. K:0 13. 5 



4. Coscinodiscus Oculus Iridis Ehb. (M. Geol. Pl. XVIII 

 fig. 42 & XIX fig. 2). Tliis very large and beautiful species 

 is very common in the arctic sea and in the northern Atlan- 

 tic. Spetsbergen- e. gr. Schoal Point, Waijgats Ids. Greenkaid 

 -also common e. gr. Davis Strait. It has been found floating 

 on tlie surface of the sea among other diatoms (Long. 61" 

 45' X Lat. 53' 43' W) and also in the content of the sto- 

 mach of Ctenodiscus, dredged from the dépth of 232 fathoms 

 ou the X.W. Atlantic 51^ 20' N 52' 25' W. 



On specimens from the arctic seas the cellules are mostly 

 large in the middle and decrease in size towards the centre, 

 where there are ahvays some few large cellules arranged into 

 a starlike group, and also towards the margin. The diameter 

 of the valve between 0,2 2 — 0,31 m.m. 



The median cellules were found to be 7 — -9 in 0, 025 m.m., 

 the cellules near the centre 8 — 9 and the marginal 7 — 10 in 

 ■0,112 5 m. m. The cellules on fossil specimens from the Vir- 

 ginia dcposit were about 5 in 0,025 m.m. and on fossil spe- 

 cimens from Mors, eJiitlaud, 6 in 0,025 m.m. 



The Coscinod. Oculus Iridis occurs on the coasts of the 

 Xorth Sea (as near Cuxhaven), in the southern Baltic Sea (as 

 by Kiel) and according to Grunow in Chile, Cape of Good 

 Hope. As I have remarked in the preceeding paper I do not 

 regard C. Oc. Iridis as specifieally distinct from C. radiatus. 



5. Coscinodiscus radiatus Ehb (Sm. Syn I pag. 23 Pl. III 

 lig. 37) Spetsbergen: Kings Bay (160 fathoms) Schoal Point. 

 Beeren Eiland in mud dredged from the depth of 1200 fathoms. 

 (Diam. 0,07 5 m.m. cellules 8 in 0,o25 m.m.) Finmarken Grötsund. 



This form is of very wide occurrence; it is common ou 

 the coasts of Sweden, Great Britain, Germany and found also 

 near Cape of Good Hope (Gr.), Tahiti (Gr.), Xicobaren Ids. 

 (Gr.) Port Jackson, Australia (Cl). 



6. Coscinodiscus centralis Ehb. (i\I. Geol. XVIII flg. 39 

 {yregorij Diat. of Clyde pag. 501 Pl. XI fig. 49) very convex, 

 colour of the dry valve purple, cellules small, about 12 — 15 

 in 0,0 2 5 m.m. Diam. 0,2 6 — 0,31 m.m. 



Spetsbergen: Waijgats Ids. (30 — 80 fths.). Davis Strait 

 Lat. 61° 45' Long. 53' 43' floating on the surface among Chse- 

 tocereai and other diatoins. 



