SARCOSPORIDIA 



189 



and simple, in other cases a radially striated ectoplasmic layer is 

 present (figs. 104, 108), which has been variously described. From the 

 inner integument, which may be homogeneous or fibrous, thick or 



thin, membranes or trabecu^ pass into the 

 interior of the body, forming anastomosing 

 partitions, and so producing a system of 

 chambers of various sizes that do not com- 

 municate with one another (figs. 104, 108). 

 These chambers are occupied by sickle- or 

 bean-shaped bodies (spores or sporozoites), 

 or various developmental stages of them. 

 The oldest spores are found in the centre of 

 the Miescher's tubes or trophozoites. If they 

 are not liberated they die there, so that the 

 central chambers of the tube are empty and 

 hollow. 



In the youngest Sarcosporidia (40/4 in 

 length) from the muscles of the sheep there 

 occur, according to Bertram, small roundish 

 or oval cells (4/4 to 5^), the nuclei of which 

 are half their size, and are embedded in a 

 granular protoplasmic mass. In somewhat 

 larger, and therefore older, cylinders, the 

 investing membrane of which already shows 

 both layers, the cells have become larger (to 

 7 //,) and are more sharply outlined from each 

 other (fig. 106). These uninucleate cells may 

 be considered as pansporoblasts. In each 

 pansporoblast division of the nucleus occurs 

 (fig. 107), and meanwhile 'the pansporo- 

 blasts become isolated within the chambers, the dividing partitions 

 of which originate from the granular protoplasm which is present 

 between the pansporoblasts. The numerous uninucleate daughter 

 forms produced within the chambers become spores direct (fig. 108). 

 The process commences in the centre of the cylinders or sarco- 

 cysts, and then progresses towards the extremities, the parasites mean- 

 while increasing in size, and new pansporoblasts being continually 

 formed at the extremities (fig. 107). 



The spores (sometimes called Rainey's corpuscles), vary in shape 

 according to the species, but are also of different form individually. 

 They are mostly kidney-, bean- or sickle-shaped (fig. 109), and of 

 small size, sometimes reaching 14 //, by 3 /* to 5 //,. They are 

 apparently surrounded by a thin membrane, and at one extremity 

 (according to the discovery of L. Pfeiffer, confirmed by van Eecke, 



FIG. 104. Sat cocys. is mies- 

 cheriana from pig. Late 

 stage in which body is divided 

 into numerous chambers or 

 alveoli, each containing many 

 spores. (From Wasielewski, 

 after Manz.) 



