- 151 — 



Gomphoneminae. 

 Rhoicosphenia Grun. 



213. R. tenuissima Östr. n. sp. Tab. nostr. II, fig. 28. 



L. 0,02—0,03 mm., b. 0,002 mm. Striæ at least 25 in 0,01 mm. 



Valve clavate. In the middle a structureless area seems to be 

 present, which with lower enlargement resembles a stauros. In 

 epitheca the striæ are conspicuous, but in hypotheca I have not 

 been able to see any striation. 



KKt (1 sample). 



This small species is exceedingly delicate and hyaline and therefore 

 it is easily overlooked. 



Cymbellinae. 

 Amphora Ehb. 



214. Amphora acuta Greg. Perag. Diat de Fr. tab. XLIX, fig. 26. 

 Found only in a sample from KKt. 



Area: Arctic Ocean, Europe, Mediterranean, Morocco, Gape Horn, Magel- 

 han's Strait, Ceylon, China. 



— — var. arcuata A. S. Perag. 1. c, fig. 28. 

 KKm, KKt, KMn— CLt (3 samples). 



Area: Gulf of Mexico, Mediterranean, Seychelles, Macassar, Mazatlan, 

 Samoa. 



215. A. angusta (Greg.) Gl. Perag. Diat. de Fr. tab. L, fig. 37. 

 KKt (7 samples). 



Area: Arctic Ocean, Europe, America. 



— — var. ventricosa Greg. Perag. 1. c. fig. 39. 

 KKt (2 samples). 



Area: Arctic Ocean, Europe, Bab el Mandeb, Monterey. 



216. A. bigibba Grun. A. S. Atl. tab. XXV, figs. 66 and 74-76. 

 KKt, KMn— CLt (6 samples). 



Area: the coasts of America, Baléares, Adria, Cape of good Hope, Japan, 

 Celebes, Ceylon, Java, Galapagos. 



217. A. costata W. Sm. A. S. Atl. tab. XXV, fig. 30. 

 Found only in a sample from KKt. 



Area: New Haven, Pensacola, Colon, Porto Seguro, Campeachy Bay, North 

 Sea, Mediterranean, Adriatic, Galapagos. 



