960 THE AMERICAN NATURALIST. 
developing, still immature statoblasts, these numbers would 
have been greater later in the season. 
The statoblast consists of a central, nearly circular, disk 
surrounded by a narrow, ring-shaped float. Placed radially at 
the margin of the statoblast are a varying number of hooks; 
the variability of this number was the starting point of the 
present investigation. 
The statoblasts counted were found partly floating free in 
the preserving fluid and were partly picked out of the colonies, 
those from one colony being carefully kept together ; 827 stato- 
blasts were counted altogether, of which 635 came from known 
colonies. 
Results. — The results of countings made on all statoblasts 
and on statoblasts from known colonies only is as follows : 
CLA Eis. ALL STATOBLASTS FROM) | Prise ALL STATOBLASTS FROM 
STATOBLASTS. | COLONIES ONLY. | STATOBLASTS. | COLONIES ONLY. 
H H 7 17 11i 18 
12 106 79 18 2 I 
13 265 201 19 2 2 
14 238 186 20 o o 
15 122 93 21 I I 
16 57 47 
The quantitative study of these seriations gives the follow- 
ing constants : 
ALL. STATOBLASTS. STATOBLASTS FROM COLONIES ONLY. 
A 827 635 
M 13 13 
A 13.782 + .031 13.814 + .036 
€ 1.318 + .022 1.326 + .026 
c 9.57 +.16 9.60 +.I9 
F=— 1.758 
Type IV 
Asymmetry = + 0.0766 
Conclusions. — Since the results based on “all statoblasts " 
and on *'statoblasts from colonies” differ by less than their 
