38 ILLINOIS BIOLOGICAL MONOGRAPHS [248 



teen, for instance. A cyst brought to completion yielded spores in which 

 each of the many examined contained eight large chromosomes. These 

 spores were watched for a day and at the end of the twenty-four hours 

 delicate partitions were seen, between each two of which was contained 

 one large chromidial body. These partitions represented lines of separa- 

 tion between the eight sporozoites which were being developed (Fig. 

 255). I was unable to procure or find any liberated sporozoites by any 

 of the following methods: 1) Some spores were left on the slide in a 

 water medium; 2) others were placed in normal sodium chloride solu- 

 tion; 3) the intestinal juice of a freshly killed cricket was run under 

 a third cover slip on which were a few spores; and 4) spores were 

 placed on a small mass of fresh intestinal epithelium. In the last two 

 instances putrefaction was soon set up in the non-sterile tissues. Using 

 spores of another gregarine (Frenzelina delphinia) from a crab, I ster- 

 ilized some of the colorless blood from the heart of the crab by boiling it 

 in a test tube and used the liquid as a medium but without inciting 

 spore development. 



Cysts were crushed at various developmental stages and stained. 

 The spores were found to be well developed before the spore ducts were 

 formed, so the early stages of development are the sources of greatest 

 changes. 



Immediately after the protoplasm of the cyst becomes collected in 

 masses, small clear papillae begin to appear on the periphery of each 

 mottled mass (Fig. 244). The layer of papillae being formed, another 

 develops beneath, until the three or four outer layers of the cyst show 

 these papillae, the inner mass being residual non-metamorphosed pro- 

 toplasm. 



The papillae soon become pinched off to form tiny globular bodies, 

 each of which contains a deeply staining particle inside. These globular 

 bodies are the gametes (Fig. 251). Upon crushing and staining a cyst 

 in the gamete stage, I have repeatedly been unable to find the least evi- 

 dence of a difference in shape or size or in staining reaction between the 

 gametes from opposite poles of the cyst; i. e., from each of the two con- 

 stituent sporonts. The gametes are isogametes. That there is, however, 

 a difference between them is shown by the attraction of certain gametes 

 for others. Before the partition wall between the two sporonts is ab- 

 sorbed, the gametes of each side do not attract others from the same 

 side of the partition. But when the partition wall has dissolved and the 

 cyst is examined, it is seen to contain many 'double' gametes; i. e., 

 gametes united in pairs (Fig. 252). If taken early enough, the gametes 

 are seen to be barely contiguous at one point. The next stage observed 

 is that in which each retains its identity but is flattened on the side of 

 attachment to the other (Fig. 253). Then the identity of each becomes 



