308 156 
of N. formica Htz. shows a narrow smooth longitudinal line and that it 
perhaps is therefore not identical with N. Jelen. Grun., which has a 
longitudinal plication. The specimens examined by me have a sharp 
plication along which the striz pass, but with moderate magnifying power 
the striation along the plication is not always easy to see, it therefore is 
possible that this striation has escaped the attention of Hantzsch. 
Area for N. formica: East Indian Archipelago. 
Vivaces Grun. 
Q44, N. fluminensis Grun. V.H. Syn. tab. LXII, figs. 3—4. 
KKm, KKt, KMn—CLt (4 samples). 
Area: Campeachy Bay, Mediterranean, Adriatic, Ceylon, Borneo, Malay 
Archipelago. 
Spathulate Grun. 
245, N. distans Greg. V.H. Syn. tab. LXII, fig. 10. 
KCn s.]. (2 samples). 
Area: Europe, Bali Sound, Pacific Ocean. 
— — var. tumescens Grun. V.H. l.c. fig. 17. 
KKm, KKt (3 samples). 
Area: Campeachy Bay, Mediterranean. 
9246. N. angularis W.Sm. Perag. Diat. de Fr. tab. LXXIII, fig. 6. 
KKm, KKt, KMn—CLt (4 samples). 
Area: ubiquitous. 
Sigmoidece Grun. 
247. N. macilenta W.Sm. V.H. Syn. tab. LXIV, figs. 6—7. 
KKm, TK (2 samples). 
A'rea: Europe, Ceylon. 
Sigmata Grun. 
248. N. Sigma W.Sm. var. rigida (Ktz.) Grun. V.H. Syn. tab. LXVI, 
fig. 5. 
KKm, KKt (3 samples), 
Area: the main species ubiquitous. 
var. rigida: cum specie passim (de Toni). 
In a sample from KKt I found a small form belonging to the form- 
circle of N. Sigma with L. 0,048 mm., b. 0,006 mm., carinal puncta 10 
in 0,01 mm. Striz not visible. I consider it a dwarf-form of N. Sigma 
var. rigida, as it is too broad to be referred to var. rigidula. 
