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228 ORDER RADIO-FLA GELLA TA.as shown at Fig. 8, as well as by the temporarily modified posterior one thatusually fulfilled the office of a pedicle. Disengaging themselves from their singleor several points of attachment, the animalcules were frequently seen to swim freelyin the water with great rapidity after the manner of Oikomonas or Spumella.Fam. II. EUCHITONTD-ffi,S. K.Animalcules free-floating, secreting a variously constructed canccllatesiliceous test or lorica, which is distinguished by the invariable presence ofa central differentiated capsule ; ray-like pseudopodia extendingfrom allparts of the periphery, supplemented anteriorly by a comparatively largeand well-developed flagellate appendage. Entirely pelagic.As the members of this family possess characters that unite them more intimatelywith the typical Radiolaria than with the ordinary Flagellata, a description of eachspecific form is not included in this treatise, but a brief diagnosis only of a characteristicrepresentative of each generic group.*GENUS I.EUCHITONIA, Haeckel.Test siliceous, consisting of a flattened, biconvex, cyclically chambered,central capsule, with radially developed projecting arms, which are disposedin the same plane and chambered cyclically in correspondence withthe central disc ;the interspaces between the radiating arms filled in bya loose, unsymmetrical, siliceous network.Euchitonia Virchowii, Hkl. PL. I. FIG. 24.Central capsule discoidal, with from two to three concentric chambercycles; radiating prominences three in number, their length slightlyexceeding the diameter of the central disc, the two* anterior slightlynarrower than the single isolated median posterior one, and basallyunited ; cyclical chambers, of which the radiating arms are composed,varying from four to six in number ; flagellum massive, equalling orexceeding the length of the test, projecting from the angle between thetwo anterior arms. Diameter of the central capsule 1-375".HAB. Pelagic : Messina.In addition to the foregoing type, as many as six other specific forms are referredby Haeckel to the genus Euchitonia, in his magnificent monograph ' Die Radiolarien,'Berlin, 1862, under the respective titles of E. -Bcskmanni, E. Gcgenbauri,E, Krohnii, E. Muelleri, E. Leydigii, and E. Koellikeri.GENUS II.SPONGOCYCLIA, Haeckel.Test siliceous, consisting of a central capsule composed of concentricand symmetrical chamber-cycles, surrounded by an irregular, sponge-likelattice-work of siliceous trabeculae, this sponge-like lattice-work not developedperipherally into distinct arm-like processes.* Professor St. George Mivart recognizing the important distinction furnished by the presenceof flagella in the three genera included in this family division, has proposed ('Linnean Society'sJournal,' vol. xiv., No. 74, 1878) to separate them from the ordinary Radiolaria as a distinct sectionof the " Flagellifera."