4 SPOROZOA. 



(b) Neospobidia Schaudinn, 1900 (=AMfEBOSPOBiDiA Hart- 

 mann). 

 Trophozoites may begin to form spores when still growing 

 or even quite young ; the sporoblasts are formed by a 

 process of internal gemination ; the sporozoite is an 

 amoebula ; and the hfe-cycle is passed in as ingle host. 

 This group includes the remaining three subclasses. 



2. Subclass Cnidosporidia Doflein, 1901. 



Spore with polar filament which is tj^pically coiled within 

 a polar capsule. 



3. Subclass Sakcospoeidia Balbiani, 1882. 



Spores crescentic, without thread capsules. Cysts forming 

 long rod-like masses. Parasites of striped muscles of 

 Vertebrates. 



4. Subclass Haplospoeidia Caullery & Mesnil, 1905. 



Spores large, contauiing a single volimainous nucleus ; no 

 thread- capsules. Type of development simple. 



B. Subphylum Ciliophoea Doflein, 1901. 

 Movement effected by cilia. 

 IV. Class CiLiATA Perty, 1852. 



Organisms bear cilia throughout Hfe. 



V. Class SucTOEiA Claparede & Lachmann ( = Tentaculifera Huxley, 

 A cinetaria Lankester ) . 

 Ciliated in the young stages, but later usually attach themselves 

 to other objects, lose their cilia, and develop knobbed tentacles 

 which serve as sucking tubes. 



General Organization and Structure. 



This volume deals with the class Sporozoa as defined above, 

 and I give below a brief survey of the general organization 

 and structure of the organisms included in this group, so as 

 to give the reader a general idea of the group and to introduce 

 him to the principal technical terms employed in the 

 description of the forms. 



Modes of Life. — All Sporozoa are obhgatory parasites, and 

 there are no free-hving forms among them. Parasitic forms 

 are also found among other classes of the Protozoa, but 

 these may be regarded as free-living forms which have been 

 introduced casually into the body of their host and have 

 become adapted to a parasitic mode of life. In Sporozoa 

 the dependance has reached an extreme Hmit, and the parasites 

 have no existence apart from the hosts in which they are found 

 to occur. The transference of the parasite from one host to 

 another is effected by means of spores, which may be defined 

 as resistant seed-hke bodies, containing one or more sporozoites 

 or germs and protected by a firm envelope or capsule. The 

 spore is a contrivance to enable the parasite to withstand 

 the vicissitudes of the outside world until they pass again 

 into the body of a suitable host. Once inside the body of 

 the new host, the spore germinates and a fresh infection is 



