170 CG. D. GILLIES. 
Out of the seventeen sets of positive data, fourteen (d— 
m, r—u) show a mode of 3, and all of these except (g) 
exhibit a well defined modal preponderance. (a) 12th May, 
1916, total frequency 33, and (c) 27th July, 1916, total fre- 
quency 30, show a modal value 2—3; (q) 31st August, 1917, 
total frequency 151, has a modal range of 2—4. As these 
values include 3, it is believed that this number is the true 
mode more or less obscured by the temporarily increased 
frequency of the adjacent values. (g) 30th October, 1916, 
total frequency 100, is an intermediate case in which 38 is. 
oniy slightly in excess of the greater of the two adjacent 
values, i.e.,4. By accepting the above explanation for the 
discrepancies mentioned, it will be seen for this locality that: 
(a) 3 is the monthly modal value, hence it is a seasonal 
constant. 
(b) (a) is not invalidated by the inclusion of empty tests 
as the mode is a constant. 
(c) June appears to be a minimum in the seasonal dis- 
tribution of the species, on account of the difficulty 
in obtaining data about this period. 
2. Brisbane Gardens (Big Lagoon), Fig. 3. 7th Dec., 1915. 
No. of spines PP2 3 ASD 6 Ba, 
Frequency woe 2 A a A 
Total frequency 28 Mode 4 
N 
"S|ENPIAIPUH Jo %0 
No u spines, 
Fig. 3. Spine frequency polygon. Brisbane Botanical 
Gardens (Big Lagoon), 7th December, 1915. 
