510 PROTOZOOLOGY 



41m by 25m in cross-sections; there were no septa within the bodies; 

 minute bodies present in the masses were mostly rounded and about 

 l/i in diameter, though a few were crescentic. The questions such as 

 what species infect man, how man becomes infected, etc., are un- 

 answered at present. 



*S. tenella Railliet (Figs. 238, a; 239). In the muscles of tongue, 

 pharynx, oesophagus, larynx, neck, heart, etc., of sheep; large 

 parasites 40/x-2 cm. long with a thin membrane; spores sickleform. 



S. miescheriana (Kiihn) (Fig. 238, b). In muscles of pig; parasitic 

 mass up to 3-4 mm. by 3 mm; envelope striated; spores reniform, 

 capable of division when young (Manz). 



S. bertrami Doflein. In the muscles of horse; similar to S. miescher- 

 iana; parasitic mass up to 9-10 mm. ; envelope striated. 



S. muris Blanchard. In body muscles of rats and mice; parasitic 

 masses up to 3 cm. long; spores 13-15^ by 2.5-3^; transmissible to 

 guinea pig (Negri) which shows experimental infection in muscles in 

 50-100 days after feeding on infected muscles. 



S. rileyi Stiles. In muscles of various species of ducks; parasites in 

 muscles, opaque white in color and measure up to 5 mm. by 2 mm.; 

 spores are sausage-shaped and S-lOju by about 3jLt. 



Order 2 Haplosporidia Caullery and Mesnil 



This order includes those sporozoans which produce simple 

 spores. In some species the spores may resemble superficially those 

 of Microsporidia, but do not possess any polar filament. The exact 

 boundaries and affinities of this order to other groups are to be de- 

 termined by future investigators. 



The Haplosporidia are cytozoic, histozoic, or coelozoic parasites 

 of invertebrates and lower vertebrates. The spore is spherical or 

 ellipsoidal in form and covered by a resistant membrane which may 

 possess ridges or may be prolonged into a more or less long tail-like 

 projection. In a few species the spore membrane possesses a lid 

 which, when opened, will enable the sporoplasm to emerge as an 

 amoebula. The sporoplasm is uninucleate and fills the intrasporal 

 cavity. 



The development of a haplosporidian, Ichthyosporidium gigan- 

 teum, as worked out by Swarczewsky, is as follows (Fig. 241): The 

 spores germinate in the alimentary canal of the host fish and the 

 sporoplasms make their way to the connective tissue of various 

 organs (a). These amoebulae grow and their nuclei multiply in num- 

 ber, thus forming plasmodia. The plasmodia divide into smaller 

 bodies, while the nuclei continue to divide ib-e). Presently the nuclei 



