BY G. I. PLAYFAIR. 315 



This is a young form of the species, the ccenobia being smaller, 

 the cells few and suborbicular. The ccenobia are formed, of 

 course, by the self-division of (originally) a single individual. It 

 is not uncommon to find specimens consisting merely of two cells 

 tail to tail. In such, the subglobose shape is very distinct; as 

 the coenobia become larger, the cells become more fusiform, 



Synura australiensis, n,sp. (Pl.xlv,, f.4, 5.) 



Testte fusiformes, fronte truncates, membrana tenui glabra. 



Ccen. diam, 70-140: cell. long. 45, lat. 5-8, ap. 2^-3 /x. 



Lismore(260, 261). 



A very beautiful and distinct species; some magnificent clus- 

 ters were noted. The membrane is thin and quite smooth; the 

 test does not show as a hyaline border. No marginal setae, ap- 

 parently two contractile vesicles on each side below the centre. 



Genus Dinobryon Ehr. 



DlNOBRYON SEUTULARIA Ehr. 



Dinohryon is very rare in this district; after over two years' 

 thorough search, I have noted two isolated sprays. 

 Wyrallah, lagoon. 



Var. CONICUM, nom.nov. 



Testse hyalinse, conicai, inferne acuminata^, lateribus leviter 

 arcuatis, ore non everso. 



Lismore(260). 



Syn,, Dinohryon sertzdaria Ehr., forma, Plankt. Syd. Water, 

 p.ofo, P1.57, f.5. 



T E s s E L L A, gen.nov. 

 Character idem ac speciei. 



Tessella volvocina, n.sp. (Pl.xlv., f.6, 7.) 

 Coenobium molle, mucosum, sphsericum, cavum; e strata unica 

 cellularum exstructum, integumento mucoso, minute granuloso, 

 investitum. Cellulse (ut videtur) pulviniformes, a vertice visse 

 inaequaliter circulataj vel polygonise, psene contingentes; a latere 

 depressse, flagellis binis praeditse. Chloroplastides bineeC?), aut 

 singulse genuflex8e(?), luteo-fuscescentes vel luteo-virides, granulis 



