424 THE PROTOZOA 



SUBORDER L : OUOOSPOKITLEA. The plasmodium divides at onoe into 

 sporoblasts, each of which becomes a single spore. 



Family Haplosporidttdoe. Spores with a double envelope, the outer some- 

 times prolonged into tails or processes. Genera : Haplosporidium, Urospor- 

 idium, and Anurosporidium ; all the known species are parasitic in Annelids. 



Family Bertramiidae. Spores with a simple envelope, or with none. 

 Bertramia, with several species : B. capitellce* parasite of the ccelome of 

 Capitdla capitata ; B. asperospora, a common parasite of the body-cavity 

 of Rotifers. B. kirkmanni, described by Warren from Rotifers in Natal, 

 is stated to have several nuclei and a vacuole in the spore, and appears to 

 belong to a distinct genus. 



In this family the genus Iclthyosporidium is ranked provisionally, as the 

 mode of spore-formation is unknown as yet. Ichthyosporidium is a common 

 parasite of fishes, often lethal to an extreme degree. It occurs in the form 

 of plasmodia, sometimes irregular, sometimes more or less spherical in form, 

 scattered in various organs, but usually in the muscles or the connective 

 tissue ; the plasmodium contains numerous vesicular nuclei with distinct 

 karyosomes, and may be naked at the surface, or marked off from the sur- 

 rounding tissues by a membrane or envelope, often of considerable thick- 

 ness. The plasmodia multiply actively by plasmotomy, and an intense 

 infection is produced. Parasites with a single nucleus are also found, which 

 may either represent the planbnt stage, or may be derived from the division 

 of a plasmodium ; from them the plasmodial stage arises by multiplication 

 of the nuclei. No other stage of the parasite is known, and the method of 

 transmission remains to be discovered. 



Bertramia bufoni*, described by King (Proc. Acad. Sci. Philad., 59, p. 273), 

 is possibly a species of Ichthyosporidium or allied to this genus. 



Family Ccdosporidiidce, for the genera Codosporidium, Mesnil and Marchoux 

 and Polycaryum, Stempell : All the species known are parasites of Crustacea 

 (Phyllopoda and Cladocera). The plasmodium forms globules of fatty 

 substance in the interior ; it becomes encysted as a whole, and breaks up into 

 sporozoite-like bodies within the cyst. 



Caullerya mesnili, Chatton (803), parasite of the epithelium of the mid-gub 

 of Daphnia spp., produces, by fragmentation of the plasmodium, spores 

 with resistant envelopes containing each about thirty nuclei. Chatton 

 considers it to be intermediate between the Haplosporidiidce and Ccdo- 

 sporidiidce. ; possibly it should be referred to the next suborder. 



Blastulidium pcedopJitJiorum, Perez, referred to this family, is, according 

 to Chatton (804), a Chytridinian. Codosporidium Uatettce, Crawley, is 

 referred by Leger (C.R.A.S., cxlix., p. 239) to the genus Pdtomyces (Myce- 

 tozoa, p. 243). 



STJBOEDEB II. : POLYSPOEULEA. The plasmodium divides into sporonts, 

 each of which produces a cluster of spores. 



Two genera, each with a single species : Neurosporidium cephalodisci, from 

 the nervous system of Cephalodiscus nigrescent (Ridewood and Fantham) ; 

 and Rhinosporidium kinealyi, from the septum nasi of human beings in India 

 (Minchin and Fantham ; Boattie) ; a case has also been observed in America 

 (Wright). 



Rhinosporidium causes vascular pedunculated growths or tumours, 

 resembling raspberries, in the septum nasi or floor of the nose. In 

 sections of the growth, great numbers of the parasite are found embedded 

 in the connective tissue, while the mature cysts may be in the stratified 

 epithelium (Wright). The youngest parasites are rounded cells with a 

 single nucleus and a distinct envelope (Beattic). By division of the 

 nucleus the parasite becomes a multinucleate plasmodium, the so-called 

 " granular stage," often of irregular form, but this may be due to the action 

 of the preserving reagents. Older parasites are spherical, with the 

 envelope thickened to form a thick transparent cyst, external to which 

 a nucleated envelope is formed by cells of the connective tissue (Beattie). 

 The contents of the cyst (Fig. 177, A) become divided up into numerous 



