Arkiv för botanik

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is ni abo ut 0 s. in diameter The figure in AN HEUROR's Synopsis represent an intermediate Orm 70 p. in diameter.

t hir of the radius margina puncta pores alternat in With

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Though I thinii tho determination is correct I ive twith reservation, havin not ad the opportunit os comparing the forna rom in land with authenti specimens. iso bo the case, I uite agro urith M OSTRU Dansh Diat. j. Ail. p. 60 in the opinion, that Steph. Singarae is arillyspecificali differsent rom Steph. 8traea It i a Stronger, more luxuriant form irom hicli the recent Steph. εtraea may have develope in eourse of time. In reality the struetur of tho valve is certaini more simila than it appears to e in consequencse of the thicher alves of Steph. Niagarae. The resone o a litile lanii, centra annulus is a Charaeter common to this large forin and the large Cyclo-tellas, elongin to the sectio o Cyclotella conita.

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quent.

Ameri Cn.

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coscino discus subtilis ΕΗΒ. Vnr glacialis GRUN. f. major

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The Coscinodiscus lacustris GRUN. b, Fran JOS. L. D. Tab. 4 f. 30, mentioned in LEVE' list, is also present in the amples rom Knjasha, ut is es frequent. The greater par of the Coscinodiscus lacustris, quote for fossi Swodisti deposit fro tho Litorina-epoch, is id0ntica withiosc. Septentrionalis GRUN. Coscino discus plicatulus GRUN. Fran JoS. L. D. Tab. 4,