BY G. I. PLAYFAIR. 615 



merit of the puncta, that I have not felt able to place it under 

 that species. Cf. also Cos. binerve Lund., Desm. Suec. T.3,f. 19; 

 and Cos. zonatum Lund., I.e. T.3, f. 18. The puncta are all 

 exceedingly faint. In young forms the semicells are all simply 

 oblong, and the puncta sometimes wanting. As the plant 

 matures, the apex broadens and the ends tend to become angular. 



Cos. punctulatum Breb. 



Long. 22-28; lat. 20-24. Nuclei amylacei singulis 

 Botany (17), Guildford (23), Centennial Park (11). 



Cos. mesoleium (Rac.) mihi. (Plate xiii., fig.l). 



Cos. punctulatum Breb., subsp. mesoleium Rac, Desm. No we, 

 p.15, T.l,f.27. 



Forma adulta, n.f. 



Paullo major. Semicellulse medio non laeves, ubique irregu- 

 lariter granulate, granulis parvis, lateribus granulis 8-10, dorso 

 4-5, supra basin serie granulorum nulla. A vertice visae ellipticse, 

 levissime tumidse. Cetera ut in forma typica. Nuclei amylacei 

 bini. 



Long. 40-56; lat. 30-45; crass. 22 Up. 



Auburn, Botany (37), Collector, Centennial Park, Coogee(13) 



Forma asperrima, n.f. (Plate xiii., fig. 2). 

 Forma granulis incrassatis, marginibus lateralibus 6-10 in- 

 structis, cetera ut in forma adulta. Nuclei amylacei bini. 

 Long. 40-42; lat. 34-36^. 

 Botany (37), Centennial Park. 



Var. RH0MB0IDEU3I Rac, I.e. T. 1, f.28, forma australis, n.f. 

 (Plate xiii., fig.3). 



Semicellulse lateribus granulis 10, dorso glabro, granulis parvis 

 in lineas diagonales 5-6 trans angulos basales dispositis, lineis 

 granulorum brevibus 5-6 radiantibus intra margines apicales, in 

 medio et supra isthmum granulis nullis. A vertice semicellulse 

 granulis in lineas transversales dispositis, in medio nudae. 



