Fig. 2.—Flagellata.

1. Salpingoeca fusiformis, S.Kent (Choanoflagellata). Theprotoplasmic body is drawn togetherwithin the goblet-shapedshell, and divided into numerousspores.

2. Escape of the spores of thesame as monoflagellate andswarm-spores.

3. Codosiga umbellata, Tatem(Choanoflagellata); adult colonyformed by dichotomous growth.

4. A single zooid of the same.
   a = nucleus.
   b = contractile vacuole.
   c = the characteristic “collar” of naked streaming protoplasm.

5. Hexamita inflata, Duj.(Distomatidae);normal adult.

6, 7 Salpingoeca urceolata, SKent (Choanoflagellata)—6,with collar extended; 7, withcollar retracted within thestalked cup.

8 Polytoma uvella, Mull. sp.(Chlamydomonadidae).

9. Lophomonas blattarum,Stein (Trichonymphidae) fromthe intestine of Blatta orientalis.

10. Bodolens, Mull. (Bodonidae),the wavy filament is atractellum, the straight one isa trailing thread.

11. Tetramitus sulcatus, Stein(Tetramitidae)

12. Anthophysa vegetans, O.F.Müller (Monadidae). A typical,erect, shortly-branching colonystock with four terminalmonad-clusters.

13. Monad cluster of thesame in optical section, showingthe relation of the individualmonads or flagellate zooids to thestem d.

14. Tetramitus rostratus, Perty(Tetramitidae).
   a = nucleus.
   b = contractile vacuole.

15. Proterospongia Haeckeli,Saville Kent (Choanoflagellata);A social colony of about fortyflagellate zooids.
   a = nucleus.
   b = contractile vacuole.
   c = amoebiform cell sunk within the colonial gelatinous test compared by S. Kent to a mesoderm cell of the sponges.
   d = similar cell reproducing by transverse fission.
   e = normal cells, with their collars contracted.
   f = substance of test.
   g = individual reproducing by multiple fission, producing microzoospores, comparable to the spermatozoa of sponges.

Fig. 3.
1. Trichonympha agilis, Leidy, from gut of White Ant (Termite). 2. Opalina ranarum, Purkinje parasitic in frog rectum multinucleate adult. 3, 4. Binary fissions of same, 1-nucleat individual at final stage of fission. 5. Same encysted dejected from rectum to be swallowed by tadpole. 6. Young 1-nucleate individual emerged from cyst, destined to grow, proliferating its nuclei to adult form.
   a = nucleus.
   b = food (?) particles in Fig. 1.

Family 8.—Tetramitidae. Body pyriform, the pointed end posterior; flagella 4 anterior.

Tetramitus (Perty) (T. calycinus of Kent, Fig. 2, 11, 14), is the “calycine monad” of Dallinger and Drysdale; Trichomonas, Donné, possesses a longitudinal undulating membrane, and is an innocuous human parasite; it is possibly related to Haemoflagellates on one hand and to Trichonymphidae on the other.

Family 9.—Distomatidae. Mouth-spots two, or one, with a distinct construction; flagella symmetrically arranged; nucleus bilobed or geminate. Hexamitus (Duj.) (Fig. 2, 5), saprophytic and parasitic; Trepomonas (Duj.), freshwater; Megastoma (Grassi) (= Lamblia of Blanchard), with constricted mouth-spot and blepharoplast (kineto-nucleus) parasitic in the small intestine of Mammals, including Man.

Family 10.—Trichonymphidae. Flagella numerous, sometimes accompanied by one or more undulating membranes; cytoplasm highly differentiated; contractile vacuole absent; all parasitic in insects (all except Lophomonas in Termites—the so-called White Ants.)
Lophomonas(St.) (Fig. 2, 9); parasitic in the cockroach; Dinenympha (Leidy), Pyrsonympha (Leidy); Trichenympha (Leidy) (Fig. 3, 1).

Family 11.—Opalinidae. Flagella short, numerous, ciliform. uniformly distributed over the flat oval body; nuclei small, numerous, uniform.
Only genus, Opalina (Purkinje and Valentin) (Fig. 3, 2-6), in bladder and cloaca of the frog (usually regarded as an aberrant ciliate, but E.R. Lankester expressed doubts as to its position in the 9th edition of this encyclopaedia).

Order 2.—CHRYSOMONADACEAE. Contractile vacuole simple (in fresh-water forms) or absent; plastids yellow or brown always present; reserves fat.

Family 1.—Chrysomonadidae. Body naked, often amoeboid in active state, or sometimes with a cup-like theca, a gelatinous investment, a firm cuticle, or silicified shell; reserves fat or leucosin (starch in Zooxanthella); eye-spot present. Chromulina (Cienk.) often forms a golden scum on tanks; Chrysamoeba (Klebs); Hydrurus (Agardh), theca of colony forming branching tubes, simulating a yellow Conferva in mountain torrents; Dinobryon (Ehrb.) (Fig. 1, 8, 15); Stylochrysalis (St.); Uroglena (Ehrb.); Syncrypta (Ehrb.), and Synura (Ehrb.) (Fig. 1, 5) form floating spherical colonies; Zooxanthella (Brandt), symbiotic as “yellow cells” in Radiolaria Foraminifera, Millepora, and many Actinozoa.