1911.] NATURAL SCIENCES OF PHILADELPHIA. 467 



latter, the most noteworthy feature of published figures is a lack of 

 clear-cut details. In one of the most elaborate studies, that of Erd- 

 mann, the figured spores show vague differentiations, but, to the 

 present writer, no exact correlation can be established. The granules 

 figured by Erdmann may be the same as those sometimes seen in 

 Sarcocystis rileyi, or they may stand for the ordinary sarcospo- 

 ridian nucleus. 



There is a general consensus of opinion that sarcosporidian spores 

 show a vesicular nucleus, and this probably corresponds with the 

 vesicular nucleus of S. rileyi. As already suggested, vacuole No. 1 

 may correspond to the supposed homologue of the polar capsule of 

 myxosporidian spores. 



But neither chromatin body No. 1 nor vacuole No. 2 appears to be 

 represented in any sarcosporidian spores other than S. rileyi which 

 have hitherto been described. 



Conclusions. 



(1) The spores of Sarcocystis rileyi are 14-15,u long and 2-3/* wide. 



(2) One end is broad and rounded, the other narrow and tapering. 



(3) The cytoplasm is spongy in the central portion, nearly or quite 

 homogeneous in the narrow end. 



(4) Within, counting from the broad end, the spore shows a vacuole, 

 a chromatin body, a vacuole, a chromatin body. 



(5) Vacuole No. 1 lies in or near the broad end. It is not usually 

 very conspicuous. 



(6) Chromatin body No, 1 is next in order to vacuole No. 1. It is 

 apparently a nucleus of the massive or compact type and stains like 

 the kinetonuclei of trypanosomes. 



(7) Vacuole No. 2 lies roughly in the middle of the spore. It is 

 usually more conspicuous than vacuole No. 1. 



(8) Chromatin body No. 2 is usually nearer the narrow end than 

 the broad end. It is apparently a nucleus of the vesicular type, the 

 chromatin of which is typically aggregated into a single large karyo- 

 some. 



(9) The spores of Sarcocystis rileyi, being apparently binucleate, 

 are very different from any other sarcosporidian spores hitherto 

 described. 



Bibliography. 



Erdmann, Rh., 1910: Beitrage zur Morphologie und Entwickelungsgeschichte 

 des Hammelsarkosporids in der Maus. Centralblatt filr Bakteriologie, etc., 

 1. Abth., Orig. Bd. 53, Heft 5, pp. 510-516, Taf. 1. 



