IV. CILIATA 



191 



The Myxosporida cause serious epidemics among fishes. The pebrine of 

 the silkworm (the eggs are also infected) is caused by Nosema {Glugea) bom- 

 hycis. Rhinos poridhim hominis, a parasite of the nasal mucous membrane of 

 man in the tropics, is nearly related to the Myxosporidia. 



Order V. Sarcosporidia. 



The Sarcosporida (fig. 149) — also called Rainey's or Miescher's corpuscles — 

 occur in the voluntary muscles of vertebrates, especially mammals. They are 

 oval cysts lying in sarcolemma sacs betvifeen the fibrillas. They have a cyst, 

 the wall of which is radially striped, and inside this, in the ripe condition, are 

 spores, imbedded in a stroma, each spore containing numerous reniform or 

 falciform sporozoites. Sarcocystis miescheriana in muscles of pig; S. muris in 

 the mouse; 5. lindemanni rare in human muscle. 



At the end of the Sporozoa may be mentioned some much disputed bodies 

 of very minute size, which are found in several infectious diseases (variola, 

 trachoma, hydrophobia, etc.) and are regarded as their cause. They have been 

 united under the common head of CHLAMYDOZOA. 



Fig. 149. Fig. 150. 



Fig. 149. — Sarcocystis miescheriana, from diaphragm of pig (after Butschli). hs, 

 cyst; sp, spheres of spores. 



Fig. 150. — Paramffcfwrn awre/za in division; 2, separation of cytostome of new indi- 

 vidual from old cytostome, at an earlier stage; 3, P. caudatum, flattened and scliematic; 

 cv, contractile vacuole, expanded and contracted; k, nucleus; na, na' food vacuole and 

 one forming; nil, micronucleus; 0, cytostome; t, (', trichocysts, t', discharged. 



Class IV. Ciliata. 



The Ciliata rival the Rhizopoda in numbers and variety of form. 

 They are so complicated in structure that they were long held as multicel- 

 lular. The form is definite for the species; and in the 'ametabolous' 

 forms is unalterable, the 'metabola' can be temporarily pressed out of shape 

 in passing through a narrow space. This constancy of form is due to a cu- 



