752 MICROSCOPIC FORMS OF ANIMAL LIFE PROTO/OA 



for regarding it. like the conjugation ' of protophytes, as a true 

 generative act. 



Tlie (Joccidia (tig. 5H4) are Sporozoa which look like minute ova. 

 and which are found resting within the cells of their hosts ; the young, 

 developed from spores, are falciform in shape, and, moving about 

 actively, are able to penetrate fresh cells. They have been found in 

 the epithelium of the intestine of various forms, and in the liver of 

 vertebrates. Some parasites found in the blood (Hsemamoebidae), 

 such as Drcj'xinidinni rci mini in. Lankester, are allied to the Coccidia. 

 but are distinguished by having naked spores. Their chief interest 

 lies perhaps in their relation to various forms of malaria. 1 Among 



FIG. 58i. ( 'ni'i-iili n in nrii'in'ii/i' (Leuckart) from theliverof the rabbit : 

 ft, cyst just formed ; /<, condensed contents, the outer envelope has 

 disappeared ; r, contents divided into four sporoblasts ; d, the sporo- 

 blasts have become rounded and clearer internally; e and/, formation 

 of the falciform germ ; r/ and fe, spores more highly magnified -17 from 

 the wide, // from in front. 



the Myxosporidia is (jlnyen, the cause of the silkworm disease. The 

 Sarcosporidia are only known from the striped muscular tissue of 

 some vertebrates. 



Of the imperfectly known Myxosporidia it may be said that 

 their spores are the bodies which are known as ' psorosperms ; ' 

 while the bodies observed by Rainev and others, and wrongly 

 regarded as the cause of the cattle plague, are sarcocystids which 

 live in the muscular fibre of mammals. 



1 More and more interest is lirini: taken in this subject, and sonic; of the results of 

 recent researches are of .u'reat interest and importance. Malaria appears to lie due to a 

 Hsemamoebid which develop?- m .^na.ts of t he ^cnus Aim/t/n-lcs ; when they arrive in the 

 human subject, they appear as minute aiixebulse which live in or on the red blood 

 corpuscles; they give rise to sporocytes which multiply indefinitely, or to sexual 

 jametorytes which undertake their sexual functions as soon as they enter the 

 stomach of ;_:iiats. See Moss and Fielding Ould. (J/nni. Jonni. Mia: Sci. xliii. 

 (1900) p. 571, and a very interesting ' Nuie on the Morphological Significance of the 

 Various 1'hases nf I I;emam<ebida'.' l>y M. Hay Lankester, torn. cit. )i. ">81. The 

 student, should also consult M. A. l.aUie's ' Heclierches Zoolo^i(]lies, CytologiqueS 

 et, Iliolo^iipies siir les ( 'occidies,' in !,<//. /.iiul. Expi'n: 1890, p. 517 ct net]., and 1'r. 

 NVasielewski's H/HH <> . ,<-ii I; >i mi i\ .lena, I.S'.M;. A detailed bibliography will b(^ found in 

 I'rof. <!. Schneidi'miihrs l>n l',-i>/ii:.nri/ nix Krn nk/ic.itaerrnfffn; Leipzig, 18!)8. Tin- 

 \ ai'i'ins Memoirs of Grassi , Laveran, and I .c>jei- may be profitably studied. 



