BY G. I. PLAYFAIR. 639 



Var. FOVEOSA, n.var. (PI. xxxiv., f.9). 



Dome of the test covered with small, shallow indentations of 

 equal size, evenly disposed. The margin of the dome, however, 

 is often not crenate. 



Diam. 53-61, alt. 16-23; orif. 20-24, alt. 8-11 /x. 



Lismore(316, 337). 



Arcella dentata Ehr. 



Syn., A. stellaris Perty. Extremely rare; I have seen only 

 one example, diam. overall 200/x, out of weeds in a small pool at 

 Auburn. In outline, it was exactly as given by Penard, Faune 

 Pvhiz., p.4lL and by Cash, I.e., i., p.l27, f.21. 



Arcella megastoma Penard. (PI. xxxiv., f.lO). 



Test with a low dome, regularly arched in an even curve from 

 one side to the other, not angled nor flattened above. Base the 

 full breadth of the test, sides of the dome meeting the base at 

 an acute angle, only the extreme tip of which is rounded off. No 

 constriction above the base. 



Diam. 51-106, alt. 19-32; orif. 17-42, alt. 8-15/x. 



Auburn (159); Botany (144); Wyrallah (310); Lismore (192, 

 225). 



Var. ALTA, n.var. (PI. xxxiv., f.ll). 



Test with a dome more highly arched, but having the same 

 regular and even curve as in the type. This curve and the sharp 

 basal angles are characteristic of the species. 



Diam. 95-160, alt. 42-53; orif. 32-42, alt. 15-21/x. 



Auburn (57, 104); Botany; Wyrallah (310); Lismore (260, 316, 

 327). 



A larger size, diam. 300-306/a, was noted out of the Richmond 

 River, but this is exceptional; and whether the specimens 

 Vjelonged to the type or the variation, I cannot say, as they 

 were too broad to get on edge. The species is common and wide- 

 spread in this country; any large specimen of Arcella is almost 

 sure to belong to it. Cf. Wailes, Rhiz. fr. N. and S. America, 

 p.204, P1.15, f.1,2. 



