196 SOME NEW OR LESS KNOWN DESMIDS POUND IN N. S. WALES, 



Long. 27; lat. 23; crass, lifx. 



Murray's Lagoon, Collector. 



Cf. Cos. pyrlforme Nord., Cent. Braz., frontispiece, which in 

 general outline it very niuch resembles. That species is, however, 

 very much larger, long. = 63/i. 



Cos. COLLECTORENSE, n.sp. (T.V. f. 17). 



Cos. parvum, oblongum, dimidio longius quam latum, medio 

 sinu linoari extremo aiiipliato piofunde constrictum. Semi- 

 cellulae perfecte quadratae; angulis acute-rotundatis; lateribus 

 3-crenatis; dorso truncatae. A vertice ellipticae utrinque in 

 medio inflatione parva instructae, apicibus rotundatis. A latere 

 ovatae, basi angusto, apice rotundato, lateribus fere rectis e basi 

 divergentibus. Membrana glabra. 



Long. 32; lat. 22; crass. Ibfi. 



Murray's Lagoon, Collector. 



The nearest is Cos. tetragonum Niig., Einz. Alg. T.7, f.A5, 

 especially f. polonica Eich. ife Gutw., Alg. Nov. T.5, f.28. 



Cos. LATEREPROTR ACTUM, n.sp. (T.V. f.23). 



Cos. minimum, subquadratum, paullo latius quam longum, 

 medio sinu lineari extremo ampliato profunde constrictum. 

 Semicellulae late subreniformes, depressatae, supra basin inilatae, 

 ad apices attenuatae; dorso lato truncato. A vertice visae 

 angustae, elongato-ellipticae; lateribus fere parallelis: apicibus 

 subacute-rotundatis. Membrana glabra. 



Long. 14; lat. 20; crass 6/^. 



Rose's Lagoon, Collector. 



The only one at all like the above is Cos. subdejyressum West, 

 N. Amer. T.15, f.l5, which is reniform and minutely granular. 



Cos. QUADRIFARIUM Lund. fomia HEXASTICHA (Lund.) Nord., in 

 Alg. N. Z. p.49. 

 Forma major Nord., I.e. 

 Long. 57-62; lat. 41-46;^. 



Forma rosacea, n.f. 

 Forma paullo major, margine verrucis emarginatis 24 instructo; 

 tumore majore verrucis 28 (14+ 10 + 4) ornata. 



