226 ORDER RADIO-FLAGELLATA. 



of Dujardin. In the midst of its natatory course it was observed to project blunt 

 digitiform processes from all sides of the periphery, as shown at Fig. 10. Its 

 motions now became more sluggish, the flagellum was completely withdrawn, 

 and then suddenly, as though by magic the bursting of a rocket or other firework 

 affording perhaps the most suitable comparison fine ray-like pseudopodia were 

 shot out in every direction, and the animalcule was at once metamorphosed into 

 a typical Actinophrys. According to Cienkowski, the monadiform germs or so- 

 called "zoospores" of the Radiolarian type Collosphcera spinosa, Hkl., are furnished 

 with two subequal flagellate appendages. An account of Cienkowski's investiga- 

 tions in this connection, translated from the German, is published in the ' Quarterly 

 Journal 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. 



' Test external to capsule with cyclic chambers . . 2. Euchitonia. 

 Fam. II. Euchitonida. 



Animalcules with a 



siliceous test or lorica, 



and an indurated central 



capsule. 



{External trabecular lattice-work) 

 more or less evenly ovate . . 

 External trabecular lattice-work) Oi 

 forming arm-like processes . . H Congas tenscus. 



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-like 

 pseudopodia projecting from all parts of the periphery, supplemented at 

 one point by a long vibratile flagellum. 



GENUS I. ACTINOMONAS, S. K. 

 (Greek, atfis, ray ; monas.) 



Animalcules ovate or spherical, uniflagellate, free-swimming, or attached 

 posteriorly by a temporarily developed thread-like pedicle ; endoplasm 

 soft and plastic, emitting ray-like pseudopodia from all points of the 

 periphery ; food-particles attracted by the vibrations of the flagellum, and 

 then seized by the pseudopodia and introduced into the substance of the 

 body at any part of its circumference ; endoplast and contractile vesicles 

 usually conspicuous. 



The two species upon which the new genus Actinomonas is here founded 

 represent some of the most remarkable and interesting types of the class Flagel- 

 lata. Divested of their radiating pseudopodia, there is nothing to distinguish them 

 from the typical members of the genus Oikomonas, while by the retention of the 

 pseudopodia and removal only of the terminal flagellum, a form is produced scarcely 

 distinguishable from the stalked Radiolarian recently described by F. E. Schulze under 

 the title of Actinolophus pedunciilatus. Through this generic type, in fact, the two 

 Protozoic groups of the Radiolaria and the Infusoria-Flagellata would appear to be 

 as effectually bridged as are the last-named group and the ordinary Rhizopoda by 

 the several genera, Mastigamceba, Rhizomonas, Reptomonas, and Podostoma. 



