PROTOZOA 



11 



doubt is justified in regard to Haeckel's Protamosba primiiiva, which 

 was observed by him in pond water and differs from Protogenes in 

 having lobose pseudopodia, whilst agreeing with it in absence of 

 nuclei, contractile vacuoles, and other differentiation of structure. 



Fio. II.— Various Proteomyxa. 1- Protomyxa aurataiaca, Hacckel, plas- 

 modlam phase. The naked protoplasm shows branched, reticulate processes 

 (pseudopodia), and numerous non-contracrile vacuoles. It is in the act of en- 

 gulphing a Ceratium. Shells of engulphed Ciliata (Tintinnabula) are einhedded 

 deeply in the protoplasm a. 2. Cyst phase of Protomyxa. a, transparent cyst- 

 wall ; b, protoplasm broken up into spores. 3. Flagellula phase of Protomyxa, 

 the form assumed by the spores on their escape from the cyst. 4. Amoebula 

 phase of the same, the form assumed after a short period by the ilagellulse. 5. 

 Vampyvella spirogf/ne, Cienk., amoeba phase penetrating a cell of Spirogyra 6, 

 by a process of its prptoplasm c, and taking up the substance of the Spirogyra 

 cell, some of which is seen within the Vampyrella a. 6. Large individual of 

 Vampyrella, showing pseudopodia e, and food particles a. The nucleus (though 

 present) Is not shown in this drawing. 7. Cyst phase of Vampyrella. The 

 contents of the cyst have divided into four equal parts, of which three are 

 visible. One is commencing to break its way through the cyst-wall /; a, food 

 particles. 8. Archerina Soltoni, Lankester, showing lobose and Ulamentous 

 protopla.sm, and three groups of chlorophyll corpuscles. The protoplasm ff is 

 engulphing a Bacterium i. 9. Cyst phase of Archerina. a, spinous cyst-wall ; 

 6, green-coloured contents. 10. Chlorophyll corpuscle of Archerina showing 

 tetraschistic division. 11. Actinophryd form of Archerina. 6, chlorophyll cor- 

 puscles. 12. Protogenes priTnordialis, Hacckel {Amceia porrecta, M. Schultze), 

 from Schultze's figure. 



The structureless protoplasmic network described by Haeckel 



from spirit-preserved specimens of Atlantic ooze and identified by 

 him with Huxley's (28) Bathybius, as also the similar network 

 described by Bessels (29) as Protobathybius, must be regarded for 

 the present as insufficiently known. 



It is possible that these appearances observed in the ooze dredged 

 from great depths in the Atlantic are really due to simple Protozoa. 

 On the other hand it has been asserted by Sir Wyville Thomson, 

 who at one time believed in the independent organic nature of 

 Bathybius, that the substance taken for protoplasm by both Huxley 

 and Haeckel is in reality a gelatinous precipitate of calcium 

 sulphate thrown down by the action of alcohol upon sea-water. 

 Other naturalists have pointed to the possibility of the protoplasmic 

 network which Bessels studied in the living condition on board 

 ship being detached portions of the protoplasm of Reticularia and 

 Radiolaria. The matter is one which requires further investigation. 



Archerina BoUoni is the name given by Lankester (14) to a very 

 simple Gymnomyxon inhabiting freshwater ponds in company 

 with Desmids and other simple grejn Algae (Fig. II. 8 to 11). 

 Archerina exhibits an amceba phase in which the protoplasm is 

 thrown into long stiff filaments (Fig. II. 11), surrounding a spherical 

 central mass about Ttrtrtl'' incii in diameter (actinophryd form). 

 A large vacuole (non-contractile) is present, or two or three small 

 ones. No nucleus can be detected by careful use of reagents in 

 this or other phases. The protoplasm has been seen to ingest solid 

 food particles (Bacteria) and to assume a lobose form. The most 

 striking characteristic of Archerina is the possession of chlorophyll 

 corpuscles. In the actinophryd form two oval green-coloured 

 bodies (b, V) are seen. As the protoplasm increases by nutrition the 

 chlorophyll corpuscles multiply by quaternary division (Fig. II. 10) 

 and form groups of four or of four sets of four symmetrically 

 arranged. The division of the chlorophyll corpuscles is not 

 necessarily followed by that of the protoplasm, and accordingly 

 specimens are found with many chlorophyll corpuscles embedded 

 in a large growth of protoplasm (Fig. II. 8) ; the growth may increase 

 to a considerable size, numbering some hundreds of chlorophyll 

 corpuscles, and a proportionate development of protoplasm. Such 

 a growth is not a Plasmodium, that is to say, is not formed by 

 fusion of independent amoeba forms, but is due to continuous 

 growth. When nutrition fails the individual chlorophyll corpuscles 

 separate, each carrying with it an investment of protoplasm, and 

 then each such amoeba form forms a cyst around itself which is 

 .covered with short spines (Fig. II. 9). The cysts are not known 

 to give rise to spores, but appear to be merely hypnocysts. 



The domination of the protoplasm by the chlorophyll corpuscles 

 is very remarkable and unlike anything known in any other 

 organism. Possibly the chlorophyll corpuscles are to be regarded 

 as nuclei, since it is known that there are distinct points of afiinity 

 between the dense protoplasm of ordinary nuclei and the similarly 

 dense protoplasm of normal chlorophyll corpuscles. 



Class II. MYCETOZOA, De Bary. 



Characters. — Gymnomyxa which, as an exception to all other 

 Protozoa, are not inhabitants of water but occur on damp surfaces 

 exposed to the au-. They are never parasitic, as are some of the 

 Proteomyxa most nearly allied to them (Plasmodiophora, &c.), but 

 feed on organic debris. They are structurally characterized by the 

 fact that the amoeba forms, which develop either directly or through 

 flagellulse from their spores, always form large, sometimes very 

 large, i.e., of several square inches area,' fusion plasmodia (or 

 rarely aggregation plasmodia), and that the spores are always 

 chlamydospores {i.e., provided with a coat) and are formed either 

 in naked groups of definite shape (sori) or on the surface of peculiar 

 columns (conidiophors) or in large fruit-like cysts which enclose the 

 whole or a part of the plasmodium and develop .besides the spores 

 definite sustentacular structures (capillitium) holding the spores in 

 a mesh- work. 



Three orders of Mycetozoa are distinguishable according to the 

 arrangement of the spores in more or less complex spore-fruits. 



Okder 1. SOROPHORA, Zopf. 



Characters. — Mycetozoa which never exhibit a vibratile (monadi- 

 form) swarmspore or flagellula phase, but hatch from the spore as 

 amcebse. A true fusion plasmodium is not formed, but an aggrega- 

 gation Plasmodium by the contact without fusion of numerous 

 amoeba forms. The spore fruit is a naked aggregation of definitely 

 arranged encysted amoebae called a sorus, not enclosed in a common 

 capsule ; each encysted amoeba has the value of a single spore and 

 sets free on germination a single amoebula. They inhabit the dung 

 of various animals. 



Genera. — Copromyxa, Zopf ; CynthuKna, Cienk. ; Dictyosteliv/m, 

 Brefeld ; Acrasis, Van Tieghem ; Polyspondylium, Brefeld. 



Order 2. ENDOSPOREA, Zopf. 



Characters. — Mycetozoa always passing through the flagellula 



phase and always forming true plasmodia by fusion of amoeba 



forms. The spore-fruit is in the form of a large cyst which encloses 



a quantity of the plasmodium ; the latter then breaks up into {a) 



