5 S MANUAL OK ZOOLOGY sect, i 



All the Sporozoa are parasitic, and all are characterised 

 by the absence of pseudopodia, flagella, and cilia; and of 

 mouth and gullet, and by the formation of spores enclosed 

 in chitinoid coats. Gregarina (Fig. 24) differ from Mono- 

 cystis in having the medullary part of the protoplasm divided 

 into two sections, known as the protomerite (pr), and 

 deutomerite (deu), by a sort of partition, with, in the young 

 condition, a third division, the epimerite (ep) in front; and 

 in the more complex form of the cysts, which have delicate 

 canals or sporoducts (spd) through which the spores escape. 

 Some of the Sporozoa (Coccidium and others) are parasites, 

 not like Monocystisand Gregarina, in the cavities of organs, 

 but in the interior of cells, such as the cells lining the intes- 

 tine of higher animals. The various forms of the disease 

 known as malaria in Man have been proved to be due to the 

 presence of a Sporozoan (Hczmamceba laverani ) which in- 

 vades and destroys, at a certain stage in its life-history, the 

 red corpuscles of the blood. Another form {Apiosoma 

 bigeminum) causes the Texas fever in cattle, the infection 

 being carried by ticks. These parasites cause high fever, 

 anaemia, bloody urine, and the number of red-blood corpus- 

 cles is diminished in one week to one-sixth of the normal 

 amount. Babesia bovis in the blood of the ox causes the dis- 

 ease known as hsemoglobinurea, and another form produces 

 a similar disease in sheep. A parasite of the tzetse fly, which 

 is a flagellate haematozoan, is the cause of the tzetse disease 

 in southern Africa. These organisms live in the marrow and 

 lymphatics, and flush at intervals into the general blood 

 stream. The disease is communicated by the tzetse fly from 

 the wild game, the herds of which are the fester spots which 

 maintain the disease. The silkworm disease called pebrine 

 is due to one of the Myxosporidia, Glugea bombycis, which 

 inhabits all the tissues of the caterpillar of Bombyx mori. 



