CRYPTODli'Tl.lKilA. 51 



" In this form also the organism, at the time of 

 gamete-formation, quits its shell and penetrates into 

 some other Protozoan organism, such as Amoeba 

 j/rofeiix, in the body of which it becomes parasitic 

 and goes through the process of gamete-formation. 

 The nucleus breaks up into chrdmidia, from which 

 secondary nuclei are formed, producing a multi- 

 nucleate plasrnodium which multiplies by plasmotorny 

 until the host is full of them. Ultimately the 

 plasmodia break up into uninucleate cells, the 

 gametes, which are set free and copulate, The 

 zygote becomes ' a flagellated Rodo-\ike organism, 

 with two flagella, one directed forward, the other 

 backward as a trailing flagelluin ; it feeds and 

 multiplies in this form for several generations in the 

 free state s but ultimately it loses its flagella, becomes 

 amoeboid, forms a shell, and develops into an adult 

 Cry/ttodifflugia. Noteworthy in this development are 

 the alternation of generations between the flagellated 

 and the amoeboid phase, as in Pxeiulospom, and the 

 parasitism in the gamete-forming phases; if, however, 

 the Cryptodifflugiit, does not succeed in finding a 

 suitable host, the gamete-formation may take place 

 in the free state." 



As only one species (C. oviforini*) belonging to this 

 genus has been described by Cash, arid three 6ther 

 species are now recorded, a synopsis of the genus is 

 here given : 



Section A. Test smooth, usually compressed. 



Test oviform, slightly compressed: aperture circular, 



terminal. (1) C. oviformis. 



Test oviform, much compressed ; aperture elliptical, 



terminal. (2) C. compressa. 



Test elongate, slightly compressed ; aperture circulai*, 



oblique. (3) C. eboracensis. 



Section B. Test usually with adherent foreign particles. 

 Test pyriform, not compressed ; aperture circular, terminal, 



enlarged. (4) C. sacculus. 



