— 183 — 



In stagnant water, scarce. 



Area: Europe, S. America, Abyssinia, India. 



Tetraëdron Kütz. 



109. T. reguläre Kütz. Phyc. Germ. p. 129. Polyedrium tetraëdri- 

 cum Näg. Gatt, einzell. Alg. 1849, p. 84, t. IV B, f. 3. 



Diam. 22 — 23//. 



Area; Europe, N. and S. America, W. Indies, E. Africa, Abyssinia, Kordofan. 



110. T. bifurcatum Lagerh. in Nuova Notarisia 1893, p. 160. Po- 

 lyedrium tetraëdricum Någ. var. bifurcatum Wille. 



Diam. sine spin. 38 — 46 //, cum. spin. 50 — 59 //. (Tab. nostr. IV, 

 fig. 50.) 



Area: N. and S. America, W. Indies, Abyssinia, Kordofan. 



111. T. octaëdrieum (Reinsen) Hansg. in Hedwigia 1888, p. 131. 

 Polyedrium octaëdrieum- Reinsch. 



Diam. 25-27/;. 



Var. spinosum. P. octaëdrieum var. spinosum Reinsch. 

 Diam. sine spin. 21—26//, cum spin. 32—38 //. 

 Area: Europe. 



112. T. cruciatum West & G. S. West. Micrasterias cruciata Wal- 

 lieh in Ann. Mag. Nat. Hist. ser. 3, vol. V, 1860, p. 281, t. XIII, f. 12; 

 Staurophanum cruciatum Turn, in Kongl. Sv. Vet.-Akad. Handl. Bd. 25, 

 no. 5, 1893, p. 159, t. XX, f. 20, 21. 



Diam. 52 — 54 //. (Tab. nostr. IV, fig. 51.) 



The eight angles were bifurcate (not trifurcate) and a few of the 

 spines were again furcate. 



Amongst various Desmids, Scenedesmus, etc., in stagnant water in the jungle. 

 Area: India, Ceylon. 



Reinschiella De Toni. 



113. R. siameiisis West & G. S. West, n. sp. (Tab. nostr. IV, fig. 52.) 



Gellulæ magnæ, solitariæ et libère natantes, late lunato-lanceo- 

 latæ, margine exterioiï multum convexo, margïne interiori subrecto 

 et levissime retuso, apieibus produetis in spinas longas gracillimas 

 et recurvatas. 



Long, sine spin. 77 p; lat. 28/*; long. spin. cire. 17 — 52//. 

 Apparently a distinct species nearest to R. crassispina De Toni. 

 With various Desmids amongst Spirogyra decimina var. in stagnant water. 



