PROTOZOA IS 



a thin cuticle ; within this lies the cortical protoplasm, which, 

 though full of granules, is transparent. The medullary proto- 

 plasm is dark brown and opaque. BiitschK has shown that 

 some of the granules are composed of a starch-like material. 

 The body exhibits movements of a euglenoid character ; waves 

 of contraction passing down the elongated cell. The flowing 

 about of the protoplasm is rendered visible by the granules. 

 The nucleus is clear and vesicular, with few granules, and it 

 lies in the centre of the cell. 



At times two individuals come together and surround them- 

 selves by a spherical capsule ; apparently no true fusion takes 

 place, but the bodies of the Gregarines commence to form spores. 

 This spore formation proceeds from without inwards in each 

 cell, but the whole protoplasm is not always used up for this 

 purpose. The spores are shuttle-shaped, they acquire a capsule 

 (chlamydospores), and are often spoken of as pseudonavicdlae. 

 The pseudonavicellae escape from the cyst by its bursting, or in 

 Clepsidrina, a Polycystid, by special sporoducts. Their contents 

 divides into eight elongated bodies, known from their shape as 

 falciform bodies ; these leave the pseudonavicella, and probably 

 grow up directly into the adult form. A recent observer has, 

 however, stated that the contents of the pseudonavicella does 

 not break up into falciform bodies, but the protoplasm becomes 

 grooved, and thus the appearance of segmentation is produced. 

 According to him, the whole contents of the pseudonavicella 

 escapes and grows in a new Gregarine. 



Many of the Polycystidae are more highly differentiated 

 than the species described above ; their cuticle may be ridged 

 or tuberculated, and is frequently produced into hooks in the 

 epimerite, and the cortical layer of protoplasm may show traces 

 of fibrillation. When these septate forms conjugate, they 

 usually lie side by side. Oregarina gigantea, which inhabits 

 the alimentary canal of lobsters, attains the astonishing length 

 of |- of an inch. 



Coccidiidea are minute spherical cells which infest the 

 epithelium of the intestine, the liver cells, etc., of Vertebrates, 

 MoUusca, and Insects. Whilst still in their cell host, they 

 give rise to chlamydospores and falciform young. 



