618 SOME SYDNEY DESMIDS, 



The nearest to the above species is Cos. bacciferum Turn., Alg. 

 E. Ind. T.10, f.8, which is larger, and has the granules arranged 

 differently. Compare also Cos. tetrophthcdmum Kiitz., in Ralfs, 

 T.17, f.ll, which is quite double the size, with a linear sinus also. 



Cos. subbinale (Nord.) Lager, var. euastroideum, n var. 

 (Plate xiii., fig.8). 



Cos. parvum, duplo diametro longius, medio sinu lineari con- 

 strictum. SemicellulaB subpyriformes, angulis basalibus late- 

 rotundatis, lateribus e basi tumidis, e medio levissime retusis, 

 ad apices convergentibus, apicibus truncatis medio indentatis 

 foveis singulis instructis, angulis superioribus acute-rotundatis. 

 A latere semicellulse oblongEe, lateribus parallelis, apicibus rotun- 

 datis. Membrana glabra, ad partem inferiorem laterum et ad 

 apices (ut videtur), incrassata. 



Long. 40; lat. 22; crass. 12/z. 



Botany (37). 



Probably the fully developed form of Cos. subbinale. The 

 incrassations at the side and end seem to be only apparent, not 

 real, as they were not visible in side-view. In this it differs 

 from Eu. subincisum Rein., Cape, f. 12, to which it has a slight 

 general resemblance. Others somewhat similar are Cos. doliforme 

 West & West, N. Am. Desm. T. 15, f. 16, which is retuxe near the 

 base; and Eu. cosmarioides W. & W., Alg. Madag. T.6, f.23, 

 which is inflated above the isthmus. 



Cos. stenonotum (Nord.) var. spirale, n.var. (Plate xiii., fig. 20). 



Semicellulse pyramidatse, angulis basalibus subacutis, lateribus 

 levissime convexis paullo supra medium angulatis, apicibus 

 obtusis quam levissime truncatis, foveis singulis instructis. A 

 latere et a vertice seniicellulae semper spiraliter tortse, lateribus 

 parallelis, apicibus rotundatis. Membrana grosse scrobiculata, 

 paullo supra centrum scrobiculato-reticulata. 



Long. 83-96; lat. 45-53; crass. 20 M . 



Rose's Lagoon, Collector. 



