BY C. D. GILLIKS. 



243 



the observations, when the Arcellse were sufficiently abundant, 

 100 counts were made; but, on a number of occasions, this was 

 not done through the scarcity of the genus, the extreme case 

 being in connection with the gathering of 30th November, 1917, 

 when only five counts were recorded. 



Fig. 1, A. vulgaris. The graph shows two primary minimum 

 periods (29th Sept. -28th Nov., 1916, and 28th 8ept.-1 Nov., 1917)^ 

 and a long maximum period (28th Dec, 1916-12th Sept., 1917) 

 with three secondary maxima (30th Jan., 31st May, 31st Aug., 

 1917), and two secondary minima (28th Feb. and 28th June, 

 1917). The highest point of the curve is 84% (28th Jan., 1917), 



Oct. Nov. Dec. Ja;n. Feb. Ma.r Apl. Ma.y Jun, Jul. AuJ. Sep. Oct, Nov. Dee. 

 Fig.2. — Percentage-frequency of A. diacoides in Arcellan fauna. Ihisbane 

 Botanical Gardens : Sept. 29th, 191(3, to Dec. 291 h, 1917. 



It seems probable that the primary maximum and minimum 

 periods are typical for the species in Southern Queensland, 

 because, in the occasional material collected in the maximum 

 period Dec. -Sept., the dominant form is A. vulgaris {see Bribie 



