BY G. I. PLAYFAIR. 515 



plankton. The following list gives the forms commonly to be 

 observed in every filter-sample: — 



Ai'. ti'iangularis, Cos. elUpsoideum var. intermedium and 

 var. minor, Cos. capittdu/n var. defrifum, St. connatum. var. 

 Spenceriarium,, St. corniculatum (3 variahile, St. orhicidare 

 var. germinosum, and var. planet onicum, St. approaimafiim, 

 St. seorangulare var. platyrerum, St. sagittarium, St. volans 

 and var. elegans and var. trigonum. 



Pedinstrum duplex var. reticulatum. 



Melosira granulata, Cycl. Meneghiniana, and var. stelli- 

 gera and var. minutiss''ma, Tab. focculosa, Rhizo. eriensis 

 var. morsa, Synedra suhtdis, Vh. rhomhoides var. neglecta 

 (Schiz. neghcta Thw.), Gomphorienia parvulum, Arhnanthes 

 niirrocephala. 



Osr. nigroviridis var. rrns.'^a, Sri/t . mirabile. 



Cerat. hirundinella, Perid. fahuhifiim var. grnnulosu77i 

 and var. Westii and var. inconsplcuum . 



Anurea cochlearis, Dinohryon sert}daria var. divergens, 

 Bosmina longirostris var. cornuta. 



Almost all are quite well known European forms, such, 

 too, as are common in the waters round Sydney, and in 

 other parts of New South Wales. 



Notes on, and descriptions op various forms. 

 PH^OPHYCE^. 



DiNOBRYON SERTULARiA Ehr. , forma. (Plate Ivii., fig-5). 



I am entirely in agreement with Wesenberg-Lund (Biol. 

 Centralbl. xx.) and Kofoid (Plankt. Illinois River), who re- 

 gard all the variants of Dinohryon as forms of a single species. 

 The latter {I.e., Art. ii., pp. 78-79) after enumerating sixteen 

 "species" represented in the plankton, says : — "As the result 

 of my attempts to refer all of the individuals which I have 

 seen in my work of enumeration, to species, I am of the 

 opinion that we are dealing, in the case of the species of 



51 



