640 RHIZOPODS OF SYDNEY AND LtsMORE, 



Arcella CATiNUS Penard. (PI, xxxiv., f.l2). 



Etudes s. 1. Rliiz., p. 154, PI. v., f.87. Incorrectly identified 

 with A. artocrea Leidy, by Penard in Faune Rhiz., p. 405, f.3, 

 which is quite a different shape. Syn., A. vulgaris v. compressa 

 Cash, l.c, i, p. 138, f.28. 



Diani. 90, alt. 25; orif. 31, alt. 12/x. 



Lisraore(192). 



Var. AUSTRALis, n.var. (PI. xxxiv., f.l3). 



Test with lateral angles much more elevated above the base, 

 the dome less angular. 



Diam. 122, alt. 16; orif. 40, alt. 12//.. 



Lisraore (316).- 



Both type and variation extremely rare, only one specimen of 

 each observed. The two just cover the range of dimensions as 

 laid down by Penard, I.e. In var. australis, the basal angles 

 have become lateral, their elevation above the base in the speci- 

 men measured being 17/x Penard considers this a Sphagnum- 

 form, but I have the type horn the river, and the variation from 

 a swamp. 



Arcella costata Ehr. (PI. xxxiv., f.l4). 

 End' view circular. Diam. 64, alt. 44; orif. 17/ji. 

 Lismore (337). 



Var. angulosa (Perty) mihi. (PL xxxiv., f.l5). 

 End-view angular. Syn., A. angulosa Perty. 

 Diam. 60-63, alt. 32, ap. 39; orif. 11, alt. 8//. Lismore (337). 



Var. conica, n.var. (PI. xxxiv,, f.l6, 17). 



Test in side-view broader above than in the type, with sides 



more vertical. The apex, instead of being flat, 



rises from the shoulder into a peak, giving the 



test the shape of a marquee-tent. The peaked 



apex is som'^tiraes shaped like the roof of a 



Fig. 3. house, showing as an angle from one point of 



Arcella costata var. view, as a ridge from another. End-view 



angulosa (Perty) ^^^^^.^11 circular, with 7-10 irregular-sized 



mihi; (x 400). '^ , •., • .1 • r j u 



panels withm the margin, formed by as many 



costce. 'Ihe orifice is always remarkably small. 



