ARCHERINA BOLTONI. 
63 
oval masses lodged in the protoplasm of the sphere, as shown 
in figs. 7, 10, 11, and 13. 
Rarely the green colour is seen to be confined to a single 
spherical corpuscle (fig. 12) of half the diameter of the whole 
sphere. 
The green colouring matter is chlorophyll, identical in tint 
with that of the Desmids, Closterium, and Pediastrum, which 
abound side by side with Archerina. The chlorophyll in 
Archerina is confined to a definite “ chlorophyll-corpuscle,” a 
dense portion of the constituent protoplasm of the spherical 
body; in fig. 12 this chlorophyll-corpuscle is in a quiescent 
condition; in figs 7, 8, 9, 10, 11, 13 it is in process of 
multiplication by division. 
No other structural elements can be detected in Archerina 
in this phase of its growth either before or after the use of 
re-agents. It consists simply of a sphere of dense protoplasm 
with radiating pseudopodia, one or more large vacuoles, and a 
single or bifid chlorophyll-corpuscle. No nucleus can be 
detected in Archerina. The examination for a nucleus was 
carefully made. The chlorophyll of the chlorophyll-corpuscle 
was extracted by alcohol, and the Archerinse were then stained 
with borax-carmine ; others after similar extraction were 
stained with Kleinenberg’s hsematoxylin, others with picro- 
carmine, and some with anilin blue (aqueous solution). In 
none of these cases could any nucleus or nucleus-like structure 
be detected, excepting the chlorophyll-corpuscle itself, which 
(as is usual with chlorophyll-corpuscles) after the discharge of 
the chlorophyll exhibited a marked superiority over the sur- 
rounding protoplasm in taking up the staining agent in each 
of the above instances. 
The chlorophyll-corpuscle of Archerina, like those of Spon- 
gilla and Hydra (and like those of higher plants), appears to 
consist of modified protoplasm resembling that of a cell- 
nucleus. In this particular instance it appears that the 
chlorophyll-corpuscle is actually taking the place of 
a nucleus. As will be seen directly, the life and growth of 
the Archerina centres round its chlorophyll-corpuscle. The 
