170 SOME NEW OR LESS KNOWN DESMIDS FOUND IN N. S. WALES, 



Genus Spirotaenia Breb. 



Sp. obscuka Ralfs, Brit. Desin., p.l79, T.:U, f.2. (T.iii. f.2). 



Long. 134: lat. 24;i. 



Coogee. 



The endoehrouie is bright green and apparently diffused, but 

 on carefully focussing the surface seven darker very narrow spiral 

 bands may be seen. The spirals are even more longitudinal than 

 those figured by Ralfs, and are decidedly obscure. Terminal 

 yescicles present, but very small. 



Genus E u a s t r u m Ehr. 

 Eu. ROTUNDUM, n.sp. (T.v. f.20). 



Eu. mediocre, subduplo longius quam latum, profunde con- 

 strictum sinu lineari. Semicellulae obscure trilobatae, campanu- 

 latae: angulis inferioribus leviter rotundatis; lateribus in parte 

 inferiore convexis, in parte superiore concavis; lobo polare nngusto, 

 levissime inflato, apice truncate; angulis superioribus rotundatis. 

 incisura lineari. iSeniicellulae supra isthmum tumore unico, 

 paullo supra tumoribus binis et inter eos scrobiculis singulis 

 instructae; a latere visae, ovatae, crassae, basi lato rotuiidato, 

 apice conico. Membrana achroa, laevis 1. subtilissime punctata. 



Long. 59-68; lat. 29-30; crass. 21-24^. 



Botany. 



The nearest forms seem to be Eu. suhhexahhum West,* Eu. 

 porrectujn Borge,t Eu. intf^rmedium Cleve var. compactum West, I 

 and Eu. ansatuni (Ehr.) Schm ,§ evidently misnamed, as he cites 

 Ralfs, T.14, f.2. 



The basal tumour can only be seen in J face on rolling over. 

 This species in front view is very like an immature form of Eu. 

 campamilatum mihi, but the side view is characteristic, as the 

 semicell is remarkably thick for its size, and the upper tumours 



* Some Desni. U. S. T.16. f.7. 



t Desm. Regnell. T.5, f.S. 



t Fr. Alg. Ceylon, T.19, f. 14-15. 



§ Schmidle, Alp. Alg. T.17, f.lO. 



