28 



PROTOZOA 



tractile vacuole ; c, amylon-nuoleus ; d, free oolourlesB flagellates, probably 

 not belonging to Dinobryon; e, stigma (eye-spot); /, ohromatophors. 

 16. Peranema trwiwphorum, Ehr., (one of tlie Euglenoidea), creeping 

 Individual seen from the back ; x 140. a, nucleus ; h, contractile 

 vacuoles ; c, pharynx ; d, mouth. 17. Anterior end of Euglena aeus, 



Ehr., in profile, a, mouth ; b, contractile vacuoles ; c, pharynx ; d, stigma 

 (eye-spot); e, paramylum-body ; /, chlorophyll corpuscles. 18. Part of 



the surface of a colony of Volvox globator, L. (Fhytomastigoda), showing 

 the intercellular connective fibrils, a, nucleus ; 6, contractile vacuole ; 

 c, amylum granule. 19. Two microgonidia of Volvox glohator, L. a, 



nucleus ; 6, contractile vacuole. 20. Eipe asexually produced 



daughter-individual of Volvox minor, Stein, still enclosed in the cyst 

 of the partheno-gonidium. a, young partheno-gonidia. 21, 22. 



Trypanosoma saiiguinis, Gruby ; one of the Rhizomastigina, from the 

 blood of Sana esculenta. a, nucleus, x 600. 23-26. Kepro- 



duction of Bodo caitdatu6, Duj. (one of the Heteromastigoda), after Dallin- 

 ger and Drysdale ;— 23, fusion of several individuals (Plasmodium) ; 24, 

 encysted fusion-product dividing into four ; 25, later into eight ; 26, cyst 

 filled with swarm-spores. 27. Astasia tenax, 0. F. Miill. (Proteus) ; one of 

 the Euglenoidea ; X 440. Individual with the two flagella, and strongly 

 contracting hinder region of the body, a, nucleus ; b, contractile vacuole, 

 close to the pharynx. 28. The same devoid of flagella. a, nucleus ; 



c, c, the two dark pigment spots (so-called eyes) near the mouth. 29. 



OikomoiMs termo (Monas termo) Ehr. ; one of the Manadidea. a, nucleus ; 

 &, contractile vacuole ; c, food-ingesting vacuole ; d, food-particle, x 440. 

 30. The food-particle d has now been ingested by the vacuole. 31. 



Oikomonas mutabilis, Kent (Monadidea), with adherent stalk, a, nucleus ; 

 b, contractile vacuole ; c, food-particle in food vacuole. 32, 33. Cerco- 

 monas crassicauda, Buj. (Monadidea), showing two conditions of the 

 pseudopodium-protruding tail, a, nucleus ; b, contractile vacuoles ; e, 

 mouth. 



Fam. 5. Hetkeomonadina, Biitsohli. Small colourless or green 

 monads which possess, besides one chief flagellum, one or two smaller 

 paraflagella attached near it, often forming colonies secreting a 

 common stalk. 



Genera. — Monas {Ehr.), Stein; DeTidronumas, Stein; Cephalo- 

 thamnium, Stein ; Anthophysa, Bory d. Vine. (Fig. XXI. 12, 13); 

 Dinobryon, Ehr. (Fig. XX. Sand 15); Epipyxis, Ehr.; UrogUna, 

 Ehr. (Fig. XX. 5). 



Okdbr 2. EUGLENOIDEA, BUtschli. 



Characters. — Generally somewhat large and highly developed 

 monoflagellate forms, of monaxonic or slightly asymmetrical 

 build. Cuticle present ; cortical substance firm, contractile, and 

 elastic ; some forms quite stiff, others capable of definite annular 

 contraction and worm-like elongation. At the base of the flagellum 

 a small or large mouth leading into a more or less distinct 

 pharyngeal tube. Near this is always the contractile vacuole. 

 Rarely a pair of flagella instead of one. 



Fam. 1. GcELOMONADiNA. Coloured Euglenoidea, with numer- 

 ous small chlorophyll corpuscles or 1 to 2 large plate-like green or 

 brown chromatophors. Mouth and pharynx inconspicuous ; nutri- 

 tion probably largely vegetal (holophytic). 



Genera. — Codomonas, Stein ; Gonyostomum, Dies. ; Vacuolaria, 

 Cienk. ; MicrogUna, Ehr. ; OhromuUna, Cienk. ; Crypioglena, Ehr. 



Fam. 2. Euglenina, Stein. Body monaxonic, elongated, hinder 

 end pointed. Spirally striated cuticle. A fine mouth-aperture 

 leads into the well-developed tubular pharynx. Flagellum usually 

 single, sometimes paired, often oast off. Near the pharynx is the 

 "reservoir" of the contractile vacuoles and several of the latter. 

 A single (sometimes two) stigma or colour-speck near the same 

 spot. Chromatophors nearly always present, generally bright 

 green. A large nucleus in the middle of the body. Multiplication 

 by longitudinal fission. Encysted condition and attendant fission 

 imperfectly studied. Copulation doubtful. 



Genera. — («) With flexible cuticle: — Euglena, Ehr. (Fig. XX. 13, 

 17 ; this is probably Priestley's "green matter," from which he 

 obtained oxygen gas ; though one of the very commonest of all 

 Protozoa, its life-history has yet to be worked out) ; Coladum, 

 'Ehr. ; Hutreptia, Feity. 



(b) With stiff, shell-like cuticle : — Aseoglena, Stein ; Trachelo- 

 monas, Ehr. ; Lepodndis, Perty ; Phacits, Nitzsch. 



Fam. 3. Menoidina, Biitschli. Similar to the Euglenina, but 

 devoid of chlorophyll, a deficiency connected with the saprophytic 

 mode of life. Stigma always absent. 



Genera. — \a) With flexible cuticle : — Astasiopsis, Biitschli ; Asta- 

 siodes, Biitschli. 



(b) With stiff cuticle and non-contractile body : — Monoidium, 

 Perty ; Atractonema, Stein ; Bhabdomonas, Fresenius. 

 • Fam. 4. Peeanemina. Very contractile (metabolic) colourless 

 Euglenoids. Mouth and pharynx large ; inception of solid nutri- 

 ment certainly observed. 



Genera. — Peranema, Duj. (Fig. XX. 16) ; Urceolus, Meresch. 



Fam. 5. Petalomonadina. Colourless, non-metabolic forms. 

 Mouth opening at the base of the single large flagellum. 



Genera. — Petalomonas, Stein. 



Fam. 6. Astasina. Colourless, metabolic, or stifif Euglenoids, 

 differing from the rest in having a small or large paraflagellum in 

 addition to the chief one, Nutrition partly saprophytic partly 

 animal. 



Genera,.— Astasia, Ehr. emend. Stein (Fig. XX. 27, 28) ; Setero- 

 nema, Duj. ; Zygoselmis, Duj. ; Sphenomonas, Stein ; Tropido- 

 seyphus, Stein. 



Oedek 3. HETEROMASTIGODA, Biitschli. 



Characters. —Small and large monads. Naked and even amceboid 

 or with stiflf cuticle. Two flagella at the anterior end differing in 

 size : the smaller directed forwards subserves the usual locomotor 

 function ; the larger is directed backwards and trailed, without 

 movement. Sometimes two back wardly directed flagella are present. 

 Always a mouth and animal nutrition. Always colourless. 



Fam. 1. BoDONiNA, Biitschli. Size of the two flagella not very 

 different. 



Genera,.— Bodo, Ehb. emend. Stein (Fig. XX. 23 to 26, and Fig. 

 XXI. 10 ; the hooked monad and the springing monad of Dal- 

 linger and Drysdale (66) ; Seteromita of Dujardin and Kent); 

 Phyllomitus, Stein ; Colponema, Stein ; Daliingeria, Kent ; Tri- 

 'mastix, Kent. 



Fam. 2. Anisonemina, Kent. Large forms with cuticle ; differ- 

 ence of the two flagella considerable. Mouth, pharynx, and animal 

 nutrition. 



Genera. — Anisonema, Duj. ; Entosiphon, Stein. 



Ordeh 4. ISOMASTIGODA, Biitsohli. 



Characters. — Small and middle-sized forms of monaxonic rarely 

 bilateral shape. Fore-end with 2, 4, or seldom 5 equal-sized and 

 similar flagella. Some are coloured, some colourless ; naked or 

 with strong cuticle or secreting an envelope. Mouth and pharynx 

 seldom observed ; nutrition generally holophytic (i. e. , like a green 

 plant), but in some cases, nevertheless, holozoic [i. e. , like a typical 

 animal). 



Fam. 1. AM;pHiM0N-4.Dii<rA. Small, colourless, biflagellate Iso- 

 mastigoda. 



Genera. — AnipMmonas,!)^^. (I Pseudospora, Cienk.). 



Fam. 2. Spongomonadina, Stein. Small colourless oval forms 

 with two closely contiguous flagella. Chief character in the union 

 of numerous individuals in a common jelly or in branched gelatinous 

 tubes, the end of each of which is inhabited by a single and distinct 

 individual. 



Genera. — Spongomonas, Stein ; Cladomonas, Stein ; Bkipido- 

 monas. Stein. 



[Group Phytomastigoda, BUtschli. The following three families, 

 viz., Chrysomonadina, Chlamydomonadina, and Volvocina, are so 

 closely related to one another as to warrant their union as a sub- 

 order. They are typical Isomastigoda, but have chlorophyll 

 corpuscles and holophytic nutrition with correlated deficient 

 mouth and pharynx. They are usually regarded by botanists as 

 belonging to the unicellular Algae. ] 



Fam. 3. Chktsomonadina, Biitschli. Single or colony-forming ; 

 seldom an envelope. Spherical free-swimming colonies may be 

 formed by grouping of numerous individuals around a centre. 

 With two or rarely one brown or greenish brown chromatophor; 

 a stigma (eye-speck) at the base of the flagella. 



Genera. — Stylochrysalis, Stein; Chrysopyxis, Stein; Nephrosel- 

 mis. Stein ; Synura, Ehr. ; Syncrypta, Ehr. (Fig. XX. 4). 



Fam. 4. Chlamydomonadina. Fore-end of the body with two 

 or four (seldom five) fiagella. Almost always green in consequence 

 of the presence of a very large single chromatophor. Generally a 

 delicate shell-like envelope of membranous consistence. 1 to 2 

 contractile vacuoles at the base of the flagella. Usually one eye- 

 speck. Division of the protoplasm within the envelope may pro- 

 duce four, eight, or more new individuals. This may occur in the 

 swimming or in a resting stage. Also by more continuous fission 

 microgonidia of various sizes are formed. Copulation is frequent. 



Genera. — Hymenomonas, Stein; Chlorangium, Stein; Chloro- 

 gonium, Ehr. (Fig. XX. 6, 7) ; Polytoma, Ehr. ; Chlamydomonas, 

 Ehr. (Fig. XX. 1, 2, 3); Hsematococcus, Agardh { = Ghlamydo- 

 coecus, A. Braun, Stein ; Protococcus, Cohn, Huxley and Martin ; 

 Chlamydomonas, Cienkowski); Carteria, Diesing; Spondylomoni/m, 

 Ehr. ; Coccomonas, Stein ; PhMOtus, Perty. 



Fam. 5. Volvocina. (3olony-building Phytomastigoda, the cell- 

 individuals standing in structure between Chlamydomonas and 

 Hffimatoeoccus, and always biflagellate. The number of individuals 

 united to form a colony varies very much, as does the shape of the 

 colony. _ Reproduction by the continuous division of all or of only 

 certain individuals of the colony, resulting in the production of a 

 daughter colony (from each such individual). In some, probably 

 in all, at certain times copulation of the individuals of distinct 

 sexual colonies takes place, without or with a differentiation of the 

 colonies and of the copulating cells as male and female. The 

 result of the copulation is a resting zygospore (also called zygote or 

 oo-spermospore or fertilized egg-cell), which after a time develops 

 itself into one or more new colonies. 



Genera. — Gonium, 0. F. Miiller (Fig. XX. 14) ; Stephanosphsira, 

 Cohn ; Pandorina, Bory de Vine. ; Eudorina, Ehr. ; Volvox. 

 Ehr. (Fig. XX. 18, 20). 



[The sexual reproduction of the colonies of the Volvocina is one 

 of the most important phenomena presented by the Protozoa. In 

 some families of Flagellata full-grown individuals become amcEboid, 

 fuse, encyst, and then break up into flagellate spores which develop 



