418 THE PROTOZOA 



Stem i*U (78G) brings forward a number of arguments, the most cogent of 

 which is the existence of the autocj'st separating the plasmodium of tho 

 parasite, containing the nuclei of disputed nature, from the tissues of the 

 host. 



The most recent investigations of Awerinzew and Fennor confirm com- 

 pletely StempeU's interpretation of the cysts of Qlugea anomala ; compare also 

 Weissenberg. These authors find nuclei of various sizes in the protoplasm of 

 tho cyst, larger or smaller. The larger nuclei are found in the outer, non- 

 vacuolated protoplasmic layer of the Qlugea ; they grow in length and become 

 sausage -shaped, and are ultimately segmented into smaller nuclei, which 

 may form chains at their first origin, like the meronts of Nosema and other 

 forms. In this way arise the smaller nuclei, which either become sporonts, 

 or remain as Vegetative nuclei in the protoplasmic walls of the vacuoles 

 containing the spores, where they ultimately degenerate and break up. The 

 sporonts are stated to arise tn toto from nuclei, without visible participation 

 of tho protoplasm of the cyst ; they become enclosed separately in vacuoles, 

 within which each sporont forms a cluster of spores. Thus,, in older cysts 

 the central part of the body becomes divided by tine protoplasmic partitions 

 into a mass of separate chambers or vacuoles, each containing ripe spores. 

 Glugea anomala is to be regarded, therefore, as a colonial organism in which 

 meronts and sporonts, homologous with those of Nosema, etc., lie embedded 

 in the protoplasm of their own cyst the meronts in the peripheral zone of 

 growth, the sporonts and spores in the central protoplasmic region of the 

 cyst. 



Classification. The two types of the trophic phase that have been do- 

 scribed in the foregoing paragraphs have been utilized by Perez (779) to sub- 

 divide the Microsporidia into two suborders, as given below. Stempell 

 (785), on the other hand, divides the group into three families ; the un- 

 certainty that prevails at present with regard to the exact structure of the 

 trophic phases in some forms is a hindrance to finality in the classification 

 of this order. 



SUBORDER I. : SCHIZOGENEA (sou Oligosporea). The principal trophic phase 

 is a uni nucleate meront which multiplies by fission, and from which the sporont 

 finally arises. Several genera, characterized by the number of spores produced 

 by the sporont : One spore, Nosema ; two spores, Perezia ; four spores, Ourleya ; 

 eight spores, Thelohania ; sixteen spores, Duboscqia (see below) ; n spores, 

 Pleistophora ; but Stempellia (Leger and Hesse, 776), for 8. mutabilis, parasite 

 of the fat-body of Ephemerid larvae, produces spores to the number of eight, 

 four, two, or one indifferently ; Ociosporea, the species of which are parasitic 

 in Muscidoe, produces eight spores in one species, one in another. These 

 anomalies indicate that the classification by the number of spores produced 

 by the sporont is purely artificial (Chatton and Krempf). Telomyxa glugci- 

 formis (Leger and Hesse), also from the fat-body of Ephemerid larva;, pro- 

 duces ight, sixteen, or n spores, and stands apart from all other known 

 Microsporidia in possessing two polar capsules in the spore. 



SuBOBDEBlI. i BLASTOGENEA (seu Polysporea). The principal trophic phase 

 is a multinucleate plasmodium producing sporonts by internal cleavage ; 

 example : Qlugea, To this section, also, the peculiar form Myxocystis has 

 been referred, which was discovered by Mrazek in the body-cavity of Oligo- 

 chaetes. Myxocystis occurs in the form of large masses floating freely in the 

 body-cavity, each mass remarkable for an envelope composed of a fur of 

 vertical filaments, not unlike stiff cilia, and enclosing nuclei and spores in 

 various stages of development. According to the most recent investigations 

 of Mrazek, however, each of these masses represents in reality a lymphocyte 

 containing numerous parasites, which multiply and form spores, and provoke 

 a great hypertrophy of the host-cell, accompanied by multiplication of its 

 nucleus. Hence the true Myxocystis is an intracellular parasite referable, 

 apparently, to the order Schizogenea, and characterized chiefly by the peculiar 

 form of its,, spores. Diiboscqia legeri, Perez (780), from the body-cavity of 

 Termes lucifugus, is perhaps an organism of similar nature ; it is described 



