Sporozoa 325 



more nearly ovoid in cardiac muscle. Mature cysts may reach a length of 

 25-50 mm and the larger ones contain several million "spores." The sarco- 

 cyst membrane (Fig. 6. 34, J, K) is composed of two or three layers, and 

 is enclosed in a zone of loose connective tissue and sometimes a layer 



Fig. 6. 34. AD. Spores of Sarcosporidia: A. Sarcocystis platydactyli, from 

 lizards; nucleus near blunt (posterior?) end, a central vacuole, and a granule 

 at the pointed end; x4750 (after Ball). B. S. lacertae, from lizards; x3120 

 (after Badudieri). C. 5, tenella, x3120 (after Badudieri). D. S. muris, x3120 

 (after Badudieri). E-I. Sarcocystis muris in muscle of rat; E-H, x3120; I, x48 

 approx. (after Badudieri). E, F. Transverse and longitudinal sections, initial 

 stage of development. G, H. Successive stages in early development of a 

 sarcocyst. I. Mature sarcocyst. J. Sarcocystis miescheriana, from pig; section 

 showing outer striated "membrane" and portion of a sarcocyst containing 

 spores; xl440 (after Badudieri). K. Sarcocystis tenella, portion of a sarcocyst 

 membrane and adjacent developing spores; xl440 (after Badudieri). 



of fibrous tissue. From the membrane, trabeculae extend inward to 

 form numerous compartments, many of which are filled with "spores" 

 (Rainey's corpuscles) in the mature sarcocyst. The striations of the so- 

 called striated membrane at the periphery of the sarcocyst seem to be 

 continuous with the connective tissue of the adjacent muscle fibres. 



