THE SPOROZOA 



303 



has received divers interpretations. While some observers regard 

 the striation as due to the presence of fine pores or canalicules 

 traversing a clear envelope, others, amongst whom are the most 

 recent investigators, Laveran and Mesnil [119], declare the striation 

 to be caused by a thick fur of fine filaments, planted vertically 

 to the surface of the trophozoite, and serving to attach it to the 

 fibrillae of the muscle -fibres. Both these views perhaps contain 

 something of the truth ; the external envelope probably arises 



FIG. 119. 



Sarcocystis miescheriana (Kiihn) from 

 the pig ; late stage in which the body lias 

 become divided up into numerous cham- 

 bers or alveoli, each containing a number 

 of germs. (From Wasielewski, after Manx.) 



Fio. 120. 



Sarcocystis of the ox ; section of 

 a stage similar to Fig. 119. a, sub- 

 stance of muscle-fibre ; b, envelope 

 of parasite ; c, nuclei of the muscle ; 



d, parasitic germs (gymnospores) ; 



e, walls of the alveoli. In the peri- 

 pheral alveoli are seen immature 

 germs. (From Wasielewski, after 

 Van Eecke.) 



from a stiff, radially striated ectoplasmic layer, such as is met 

 with amongst some Myxosporidia, 1 which, by breaking down of 

 the substance between the striations, is converted into a furry 

 envelope. The inner coat is formed of a thin homogeneous 

 membrane, prolonged externally into the filaments, and internally 

 into the system of chambers previously described. Internally to 

 the two coats lies the protoplasmic body of the trophozoite, com- 

 parable to the endoplasm of the Myxosporidia, and consisting 



1 Compare especially Myxidium lieberk'dhnii above, p. 281, Fig. 88. 



