PROTOZOA 



27 



in. nl,: erroneously to external parasitic organisms, which have 

 nothing in common with the Sporozoa. This w;is tlie case in regard 

 to a fungoid growth in human hair the so-called "chignon 

 ilregariiK'. " Tne Silk-worm disease known as "pebrine" lias also 

 been attributed to a Gregarine. It seems probable that the parasitic 

 organism which causes that disease is (as is also the distinct parasite 

 causing the disease known as "flaccidezza" in the same animals) 

 one of the Schizomycetes (Bacteria). No disease is known at 

 present as due to Sporozoa, although (e.g., the A7></</ I'/iitonis) 

 they may lead to atrophy of the organs of the animals which they 

 infest, in consequence of their enormous numbers. Coccidia and 

 Sarcocystis are stated to occur in Man. 



CLASS II. FLAGELLATA, 1 Ehrenberg. 



Characters. Corticata in which the dominant phase in the life- 

 history is a corticate flagellula, that is. a nucleated cell-body pro- 

 vided with one or a few large processes of vibratile protoplasm. 

 Very commonly solid food particles are ingested through a distinct 

 cell mouth or aperture in the cortical protoplasm, though in some 

 an imbibition of nutritive matter by the whole surface and a nutri- 

 tional process chemically resembling that of plants (holophytic), 

 chlorophyll being present, seems to occur. 



Conjugation followed by a breaking up into very numerous minute 

 naked spores is frequent in some ; as also a division into small 

 individuals (microgonidia), which is followed by their conjugation 

 with one another or with big individuals (macrogonidia) and subse- 

 quent normal growth and binary fission. 



Many have a well-developed cuticle, which may form collar-like 

 outgrowths or stalk-like processes. Many product either gelatinous 

 or ehitin-like shells (cups or coanrecia), which are connected so as to 

 form spherical or arborescent colonies ; in these colonies the proto- 

 plasmic organisms themselves produce new individuals by fission, 

 which separate entirely from one another but are held together by 

 the continuity, with those already existing, of the new shells or 

 jelly-houses or stalk -like supports produced by the new individuals. 

 A single well-marked spherical nucleus, and one or more contractile 

 vacuoles, are always present in the full-grown form. 



Often, besides ingested food-particles, the protoplasm contains 

 starch granules (amylon nucleus), paramylum corpuscles, chromato- 

 phors and chlorophyll corpuscles, some of which may be so abundant 

 as to obscure the nucleus. One or two pigment spots (stigmata or 

 so-called eye-spots) are often present at the anterior end of the body. 



SUB-CLASS I. Lissoflagellata, Lankester. 



Never provided with a collar-like outgrowth around the oral 

 pole. 



ORDER 1. MONADIDEA, Biitschli. 



Characters. Lissoflagellata of small or very small size and 

 simple structure; often naked and more or less aiiKeboid, sometimes 

 forming tests. Usually colourless, seldom with chromatophors. 

 With a single anterior large flagellum or sometimes with two 

 additional paraflagella. A special mouth-area is often wanting, 

 sometimes is present, but is never produced into a well-developed 

 pharynx. 



Fam. 1. RHIZOMASTIGINA, Biitschli. Simple rnouthless forms 

 with 1 to 2 flagclla; either permanently exhibiting a Gymnomyxa- 

 like development of pseudopodia or capable of passing suddenly 

 from a firm-walled into a Gymnomyxa-like condition, when the 

 flagclla may remain or be drawn in. Ingestion of food by aid of 

 the pseudopodia. 



Genera. Mrtstiyamceba, F. E. Schultze; Ciliophrys, Cienkowski 

 (65); Dimorpha, Gruber; Actinomonas, Kent; Trypanosoma, Gruby 

 (parasitic in the blood of Frogs and other Amphibia and Reptiles, 

 Fig. XX. 21, 22). The Rhizomastigina might all be assigned to 

 the Proteomyxa, with which they closely connect the group of 

 Flagellata. The choice of the position to be assigned to such a 

 form as Ciliophrys must be arbitrary. 



Fam. 2. CERUOMOXADINA, Kent. Minute oblong cell-body 

 which posteriorly may exhibit amoeboid changes. One large 

 anterior flagellum. Mouth at the base of this organ. Reproduc- 

 tion by longitudinal fission and by multiple fission producing 

 spores in the encysted resting state. 



Genera. Ccrcomonns, Duj. (Fig. XX. 32, 33); Hcrpetomonas, S. 

 Kent; Oikmnonas, Kent ( = j)/cmas, James Clark; Pscudospora, 

 Cienkowski, Fig. XX. 29, 3d, 31) ; Ancijrononas, S. K. 



Fam. 3. CODOXCECINA, Kent. Small colourless monads similar 

 to Oikotnonas in structure, which secrete a fixed gelatinous or 

 membranous envelope or cup. 



Genera. Cudonceca, James Clark; Plritythacca, Stein. 



Fain. 4. BIKCECIXA, Stein. Distinguished from the last family 

 by the fact that the monad is fixed in its cup by a contractile 

 thread-like stalk ; cup usually raised on a delicate stalk. 



Genera. Bicosaiai, J. Cl. ; Poteriodendron, Stein. 



1 Butschli's work (9) luis been pretty closely followed in tlte diagnosis of the 

 groups of Flaijellata and the enumeration of genera here given. 



FIG. XX. Flagellata. 1. Chlamydomonas vulciteulus, Ehr. (=Zygoselmis, 

 From.) ; one of the Phytomaetigoda ; free-swimming individual, a, nucleus ; 

 &, contractile vacuole ; c, starch corpuscle ; rf, cellulose investment ; 

 e, stigma (eye-spot). 2. Resting stage of the same, with fourfold 



division of the cell-contents. Letters as before. 3. Breaking up of 



the cell-contents into minute bithigellate swarm -spores, which escape, 

 and whose history is not further known. 4. Syjicrypta volvox, Ehr. ; 



one of the Phytomastigoda. A colouy enclosed by a common gelatinous 

 test c. a, stigma; b, vacuole (non-contractile). 5. Cwfjlena volvox, 



Ehr. ; one of the Monadidea. Half of a large colony, the flagellates 

 embedded in a conmiun jelly. 6. Chlaroyonium co'-h^n-n in, Ehr. ; 



one of the Phytomastigoda. a, nucleus; 6, contractile vacuole; c, starch 

 grain; /, eye-spot. 7. Chlorogonium curhlorum, Ehr., one of the 



Phytomastigoda. Copulation of two liberated microgonidia. a, nucleus; 

 b, contractile vacuole ; rf, eye-spot (so-called). S. Colony of Dinobryon 



sertitla/'ia, Ehr.; x 200; one of the Monadidea. 1*. Bxmato- 



coccus palustris, Girod (= Chlamydococcus, Braun, Protoeoccits Cohn), 

 one of the Phytomastigoda ; ordinary individual with widely separated 

 test, a, nucleus; b, contractile vacuole; c, amylnn nucleus (pyrenoid). 

 10. Dividing resting stage of the same, with eight fission products in 

 the common test e. 11. A microgonidium of the same. 12. 



Phalansteriitjit cnn^n-intnm, Cienk., one of the Choanofiagellata ; 

 X 325. Disk-like o>l"iiv. 13. Eu-jlcna nVn/iX Ehr.; x 300 ; one of 



the Euglenoidea. a, pigment spot (stigma) ; 6, clear space ; c, paramylum 

 granules ; d f chromatopnor (endocbrome plate). 14. Gvnium pectorals, 

 0. F. Mtiller ; one of the Phytomastigoda. Colony seen from the flat side. 

 X 300. a, nucleus ; b, contractile vacuole ; c, amylon nucleus. 15. 



Dinobryon sertularia, Ehr. ; one of the Monadidea. a, nucleus ; b, con- 



