458 BIOLOGY OF THE PROTOZOA 



it may divide into two {E), four {¥), or eight {(I), sporoblasts each 

 of which forms a single spore after chromidia formation and recon- 

 struction of small nuclei {H, I), some of which take part in the 

 formation of the capsular thread. A more simple life history is shown 

 by Thelohania legeri according to Kudo (Fig. 191). 



Classification of the IMicrosporidia has been in a most unsatisfac- 

 tory state but recent monographs on the group have done much 

 to remedy the situation. The minor subdivisions given below do 

 not difi'er much from those which have served the purpose for many 

 years. One innovation is the inclusion amongst IVIicrosporidia of 

 some of the genera hitherto included in a special major division 

 —the Haplosporidia. Recent investigations, particularly by 

 Debaisieux, indicate that species of the type genus Haplosporidium 

 should be included with the Microsporidia and are so treated 

 here. Certain species of the Family Bertramidae included by 

 Caullery and Mesnil in the Haplosporidia, are also grouped with 

 the Microsporidia; while the tj^Dical forms of Coelosporidia, e. g., 

 Coelosp< iridium and Rhinos par idiiim, are apparently not Sporozoa 

 at all, but belong to the Chytridiacese (see Debaisieux, 1916, 1920 

 for Coelosporidiinn, and iVshworth, 1923 for Rhinos poridmm) . This 

 leaves only certain species of Bertramia and a group of the incertcB 

 sedis in the old Haplosporidia, and with Debaisieux, we believe that 

 this subdivision of the Neosporidia may well be abandoned. 



Order 2. Microsporidia, Balbiani (1882). 



Sub-order 1. Monocnidea, Leger and Hesse (1922). 

 Spores with one polar capsule and one typical!}' coiled polar filament. 

 Family 1. Nosematidse, Labbe (1899). Spores oval, ovoid or pyriform; 

 if subcylindrical the length is less than four times the breadth, 



1. Genus Nosema, Naegeli (1857). Each sporont develops into a single 



spore. Widely distributed parasites particularly in insects. N. 

 bombyces, the cause of pebrine in silkworms; A^. apis, Zander, the 

 cause of wide-spread epidemics in honey bees; other species are 

 parasitic in Protozoa, copepods, Diptera and Lepidoptera, crabs and 

 crayfish. 



2. Genus Glugea, Thelohan (1891). Each sporont forms two spores; 



host cells hypertrophied ; forming so-called glugea-cysts. Muscle 

 and connective tissue of fish, amphibia, annelids and copopods. 



3. Genus Perezia, Leger and Duboscq. Each sporont forms two spores; 



host cells not hypertrophied. Parasites in gregarines {Lankesteria) 

 and in Lepidoptera. 



4. Genus Gurleya, Doflein (1897). Each sporont produces four spores; 



parasites of copepods and insects. 



5. Genus Thelohania, Henneguy (1892). Each sporont develops into 



eight sporoblasts, each of which forms one spore. Parasites of 

 copepods, decapods and insects, particularly mosquitoes. 



6. Genus Stempellia, Leger and Hesse (1922). Sporonts develop into one, 



two, four, or eight sporoblasts, each sporoblast forms one spore. 

 Parasites of insects. 



