THE SPOROZOA 317 



of the endoplasm ; the corpuscles multiply by fission, forming Strepto- 

 coccus-like bands, which spread through the host ; finally, fusiform cysts 

 are formed, arranged with their long axis parallel to that of the Gregarine, 

 and containing a number of nucleated corpuscles. The fusiform bodies 

 probably represent the resistent phase which serves to infect fresh hosts. 

 The type is M. spionis, C. and M., from Gregarina (Polyrhabdina, Ming. = 

 Selenidium, Giard T) spionis, Kolliker, parasite of Spio martinensis. Other 

 species are known from the Gregarines of other Annelids. 



Hyalosaccus, Keppene, 1899, for H. ceratii, Kepp., a parasite of 

 various Dinoflagellata. As it is described by its discoverer in the Kussian 

 language, the reader anxious for further information is referred to the 

 original memoir [130&]. 



Rhaphidospora, Leger, 1900, for R. le danteci, Leg., parasite of the 

 intestinal cells of Olocrates gibbus. Specimens of this beetle, which belongs 

 to the family Tenebrionidae, are found, in which the epithelial cells of the 

 mesenteron are filled with rods resembling the rhaphides of plants, lodged 

 in vacuoles and arranged parallel to the axis of the cell. Each rod is 

 about 14 p. in length by 1-5 p. in breadth, and consists of a fine membrane 

 enclosing deeply-staining filiform elements, which apparently are four in 

 number, each with a chromatin granule. The filiform elements become 

 liberated and appear to multiply by transverse fission, but ultimately 

 they grow into rods, each at first consisting of finely granular protoplasm 

 and a nucleus containing a few chromatin granules. Each such body 

 then surrounds itself with a membrane, and its contents break up into 

 filiform elements. All stages of the parasite are capable of active move- 

 ments. The rods are probably the agents by which new hosts are infected, 

 through being swallowed with the food. 



Chytridiopsis, Aimd Schneider, 1884, for C. socius, A. S., intracellular 

 parasite of the intestinal epithelium of Blaps mortisaga ; sometimes occur- 

 ring also within the Gregarine, Stylorhynchus longicollis, found in the 

 same host. The youngest stage of the parasite is a small spherical proto- 

 plasmic body, which, according to Schneider, is without a nucleus, but it 

 seems more probable, even from Schneider's figures, that it has numerous 

 small nuclei. The parasite grows to a certain size and then becomes 

 encysted. Within the tough, doubly-contoured cyst-envelope a zone of 

 cortical granular protoplasm is separated off, and within this cortical zone, 

 which appears to represent residual protoplasm, the body of the parasite 

 divides up into a great number of simple spherical spores, about 1'5 p. in 

 diameter and quite undifferentiated, forming a solid mulberry -like mass 

 occupying the centre of the cyst. By its spores and general appearance 

 Chytridiopsis seems to approach very nearly to the Haplosporidia. 



Chitonicium, Plate, 1898, for C. simplex, Plate, parasite of the mantle- 

 cavity and the epithelium of the mantle groove, foot, and gills of Ischno- 

 chiton minator, and infecting also less abundantly Chaetopleura peruviana 

 and other chitons of Chili. It occurs as little oval or spherical cells, 

 each with a distinct nucleus and cell-membrane, which multiply actively 

 by direct amitotic division in the epithelial cells, causing great destruc- 

 tion amongst them. The parasites are also found free in the mantle- 

 cavity, and multiply in this situation, where Plate thinks it possible that 



