ORIGINS OF AGAMIC PATTERNS 607 



The peculiar multinucleate spores of the subclass Cnidosporidia of the 

 Sporozoa exhibit great variety of pattern in different species (Dofiein- 

 Reichenow, 1929). They possess a distinct polar organization, some are 

 flattened in a plane of the polar axis, some are elongated at right angles 

 to the polar axis, others have long, tail-like extensions of the envelope, 

 and still others (order Actinomyxidia) develop a triradiate pattern about 

 the polar axis, the envelope in some species giving rise to long slender 

 processes and the whole spore resembling a three-armed or, in another 

 species, a six-armed grappling hook. These spores possess one, two, three, 

 or four polar capsules, each containing a spirally coiled thread which is 

 extruded under certain conditions — for example, in some forms on ex- 

 posure to intestinal fluids, or experimentally to various agents — and is 

 supposed to aid in anchoring the spore. These capsules resemble nema- 



FiG. 190, A, B. — Development of microgametes of other Sporozoa. A, developmental 

 stage of a coccidian microgamete, Aggregata spinosa (after Moroff, 1908); B, developmental 

 stages of a haemosporidian microgamete, tertian fever parasite (after Schaudinn, 1902). 



tocysts of coelente rates. They are situated at, or symmetrically about, 

 one pole, or in some species one at each pole. The spore contains one or 

 more cells from which the new generation develops. 



Spores of these types develop in most species from cells descended by 

 division from a "pansporoblast," two, four, eight, or many spores de- 

 veloping from one pansporoblast, according to species. A definite number 

 of cells, different in different forms, attains a polar arrangement; certain 

 of them give rise to the polar capsules; others to the envelope, which 

 develops great variety of form, and to one or more "germs"; or a multi- 

 nucleate mass gives rise to the new individual. There is no visible indica- 

 tion of axiate pattern in the so-called "germ." In some forms the nuclei 

 of cells giving rise to different parts of the spore become visibly distin- 

 guishable early in spore development. In the order Myxosporidia the 

 cells from which spores develop arise inside an amoeboid body by delimi- 



