HAPLOSPORIDIA. 369 



IV. Subclass HAPLOSPORIDIA Liihe, 

 1900. 



Haplosporidia are characterized by the presence of large 

 spores, each containing a single voluminous nucleus, but no 

 polar capsule, and showing a simple type of development. The 

 young parasite is an amoebula, which at first multipHes by 

 fission. The nucleus of each daughter-cell multiplies repeatedly 

 and produces a multinucleate plasmodium. The plasmodium 

 may divide (plasmotomy) or produce merozoites (schizogony) 

 or form spores. The spores are produced from sporoblasts, 

 each forming a single spore, or from pansporoblasts, each 

 giving rise to a number of spores. Infection is carried by the 

 spores, which produce amoebulse and start a new generation. 



The spore is spherical or elhpsoidal, and is covered by 

 a resistant membrane which may be marked by ridges or 

 tubercles, and may be prolonged into a tail-hJke process. 

 In a few species the spore-membrane possesses a hd, which 

 opens to allow the uninucleate sporoplasm to emerge as an 

 amoebula. 



The subclass includes parasites of certain Invertebrates, 

 chiefly AnneHds, and Fish. They float freely in the body- 

 cavity fluid of the Invertebrates or infest the tissue- cells, such 

 as those of the intestine. In Fish they attack the gills or other 

 tissues, giving rise to white nodules. One species occurs 

 in the Malpighian tubules of the cockroach. The genus Ehino- 

 sporidium, species of which form httle cysts in the nasal 

 cavities of man and horse, used also to be included in this 

 subclass, but the studies of Ash worth (1923) have shown that 

 it is not a Protozoon but a fungus. 



Debaisieux (1916, 1920) has shown that certain species of 

 Haplosporidium CauUery & Mesnil and Bertramia Caullery & 

 Mesnil should be included with the Microspokidia, while 

 Coelosporidium Crawley is not a Sporozoon. In his view 

 Haplosporidia should be abandoned as a separate group. 



For classification of the Haplosporidia, Caullery and 

 Mesnil (1905) and Ridewood and Fantham (1907) may be 

 referred to. The latter divided the Haplosporidia into two 

 sections — ^the Oligosporijlea, in which each pansporoblast 

 produces only a small number of spores or a single spore, 

 and the Polysporulea, in which the pansporoblast gives rise 

 to many spores, either successively or almost simultaneously. 

 No one has as yet studied Haplosporidia in India. 



SPOR. 2 B 



