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226 ORDER RADIO-FLAGELLATA.of Dujardin. In the midst of its natatory course it was observed to project blunt10. Itsdigitiform processes from all sides of the periphery, as shown at Fig.motions now became more sluggish, the flagellum was completely withdrawn,and then suddenly, as though by magic the bursting of a rocket or other fireworkaffording perhaps the most suitable comparison fine ray-like pseudopodia wereshot out in every direction, and the animalcule was at once metamorphosed intoa typical Actinophrys. According to Cienkowski, the monadiform germs or socalled"zoospores" of the Radiolarian type Collosphcera spinosa, Hkl., are furnishedwith two subequal flagellate appendages. An account of Cienkowski's investigationsin this connection, translated from the German, is published in the ' QuarterlyJournal of Microscopical Science,' vol. xi., No. xliv., 1871.FAMILIES AND GENERA OF RADIO-FLAGELLATA.Fam. I. Aetinomonadidce. \Animalcules naked, no I Animalcules free-swimming or attached posteriorly\ ,, ..exoskeleton or central[by a thread-like pedicle }l. Actinomonas.capsule.Fam. II. Euchitonida.Animalcules with asiliceous test or lorica,and an indurated centralcapsule.'Test external to capsule with cyclic chambers . . 2. Euchitonia.trabecular lattice-work)less evenly ovate . .more orExternal trabecular lattice-work) Oi{External forming arm-like . .processes H Congastenscus.Fam. I. ACTINOMONADID-ffi, S. K.Animalcules ovate or spheroidal, fixed or freely motile, entirely naked,possessing neither an indurated test nor a central capsule ;fine ray-likepseudopodia projecting from all parts of the periphery, supplemented atone point by a long vibratile flagellum.GENUS I.ACTINOMONAS,S. K.(Greek, atfis, ray ; monas.)Animalcules ovate or spherical, uniflagellate, free-swimming, or attachedposteriorly by a temporarily developed thread-like pedicle ; endoplasmsoft and plastic, emitting ray-like pseudopodia from all points of theperiphery ; food-particles attracted by the vibrations of the flagellum, andthen seized by the pseudopodia and introduced into the substance of thebody at any part of its circumference ; endoplast and contractile vesiclesusually conspicuous.The two species upon which the new genus Actinomonas is here foundedrepresent some of the most remarkable and interesting types of the class Flagellata.Divested of their radiating pseudopodia, there is nothing to distinguish themfrom the typical members of the genus Oikomonas, while by the retention of thepseudopodia and removal only of the terminal flagellum, a form is produced scarcelydistinguishable from the stalked Radiolarian recently described by F. E. Schulze underthe title of Actinolophus pedunciilatus. Through this generic type, in fact, the twoProtozoic groups of the Radiolaria and the Infusoria-Flagellata would appear to beas effectually bridged as are the last-named group and the ordinary Rhizopoda bythe several genera, Mastigamceba, Rhizomonas, Reptomonas, and Podostoma.