162 
SYDNEY HICKSON AND .T. T. WADSWORTH. 
water canal two kinds of free-swimming gemmulm were 
observed : a large kind which was plano-convex in side 
view (fig. 1), provided with a band of several rows of cilia and 
from six to ten contractile vacuoles ; and a smaller kind 
(fig. 31), biconvex or loaf-shaped in side view, with an 
equatorial band of three or four rows of cilia and pi-ovided 
with only three or four contractile vacuoles. 
lu this material, however, we have found the Acinetaria 
attributed to the genera Trichophrya and Lern^ophrya 
associated with Dendrosoma, and until recently we had no 
definite evidence as to wliich of the three forms the gemmulas 
belonged. 
In the material obtained from Birmingham no Tricho- 
phrya nor Lernseophrya forms were found, and the 
gemmulm we found were all of the larger plano-convex type 
(fig. 1). This observation suggested that the larger type 
is the gemmula of Dendrosoma; but we obtained a definite 
proof of the truth of this suggestion by our observations on 
the development of two of these gemmulte into the definite 
Dendrosoma forms as described below (p. 167). 
AVe then examined carefully all our whole mount prepara- 
tions for Lernmophrya forms showing gemmulm in the 
brood-pouches, and found that the smallest of them was 24 /u 
in diameter, and the largest about 37 fx (the outline of this 
gemmula is indistinct and the measurement probably not quite 
accurate). Tlie average diameter of eleven gemmulEe works 
out at about 29' 6 n. The measurement of a lai-ger number of 
gemmulae of Dendrosoma, in their brood-pouches, gave us 
considerably greater diameters, but there are one or two 
complications that must be mentioned before giving the actual 
figures obtained. Whereas all the Lernaiophrya gemmulae 
were approximately circular in outline, many of the gemmuhe 
of Dendrosoma, in the aspect presented to us in the fixed 
preparations, were definitely oval in outline. 
The smallest of the fully formed gemmulae was 29'6 /x 
(circular in outline), the largest 40'7 ju by 55‘5 fx (oval in out- 
line). Many of the gemmulae we measured were not fully 
