746 LIFE HISTORIES OF THE PROTOZOA. y 
of May, when the cyst drops off and a small Actinophrys with a 
number of nuclei appears. 2 
As an example of the bianca of these forms by fission, : 
we may cite the case of Gromia socialis, figured by Archer. He 
represents the body of a Gromia after having undergone a trans- a 
verse self-fission, having in each portion a nucleus with its nucle- A 
olus, the upper segment giving off branched pseudopodia as usual. 
Of the mode of development of the shelled Amcebz or Forami- 
nifera (Polythalamia), numerous and often accessible as these 
animals are, we know but little. In fact, we have only the frag- i ! 
mentary observations of Max Schultze, made in 1856, on a species 
- of Miliola sent him from Trieste. He says that this Foraminifer, 
after remaining from eight to fourteen days in the same place on 
the side of the jar, became surrounded with a thin layer of brown- 
ish mud, so that the shell was lost to view. On the 15th of May 5 
_he noticed that small, round, sharply defined bodies escaped from 
the brownish slimy mass, and after some hours as many as forty 
such bodies surrounded the Miliola. These round bodies were 
young Foraminifera in calcareous shells with one turn, but no inner | 
walls, somewhat resembling Cornuspira, and with pseudopodia 
already like those of the adult. It is probable, therefore, that the , 
shell of the young is formed within the parent. Schultze adds 
that the almost complete want of organic contents in the shell of : ) 
the parent at this time, rendered it probable that the whole or 
greater part of its body bad passed into those of the young. . 
Of the mode of development of the Radiolaria, Prof. Cienkow- 
ski afforded, in 1871, the first definite information. He states that 
*‘J. Müller saw in the interior of an Acanthometra a swarming of 3 
small monadclike vesicles, which moved about for a time, & 
then changed themselves into Actinophrys-like structures. After- . 
wards,” Heckel saw, first, in Spheerozoids, “the contents of the 
capsules break up into many vesicles, and secondly, in Sphæro- 
zoum, he observed masses of vesicles which exhibited a vibratory 
movement.” Lastly, Schneider had noticed in Thalassicolla g groups 
of ameboid vesicles with movable flagellum-like processes. 
facts rendered it probable, what Cienkowski has anne that the 
Radiolaria reproduce by motile germs, i.e., zoospore 
He studied the compound forms, such as conan and Collo- 
zoum, which are composed of aggregations of capsules (Fig. . 135 Ay 
