1880.] 



MICKOSCOPICAL JOUEISTAI. 



35 



very simular to A maibce, the latter ap- 

 pear to be independent animal forms. 



A. princeps, Elir. Pseudopodia 

 thick, cylindrical, rounded on the 

 ends, common. 



Other species are A. radiosa, 

 Ehr., with pointed pseudopodia ; 

 A. hilimbosa, Auerb., A. dijjfluens, 

 Ehr. A. actinojyhora, Auerb.; A. 

 verrucosa^ Ehr., A. Umax, Ehr., and 

 others, which, however, run toge- 

 ther and call hardly be regarded as 

 distinct species. 



2. Gen. Podostoma, CI. and L. 

 Besides the broad, locomotive pseu- 

 dopodia, these animals are provided 

 with moving flagella which seize 

 the prey. 



P. jiUgerum,, CL and L. In stag- 

 nant water with Algee and Infusoria. 



3. Gen. Petalopus, CI. and L. 

 Pseudopodia radiating from one 

 place, expanded at the ends. 



P. dijfluens, CI. and L. Form 

 rather constant, rounded behind, in 

 front abruptly cut off. 



4. Gen. P seudocldmnys, CI. and 

 L. Carapace soft, curved, shield- 

 shaped, the concave side up, a 

 central opening closed by a thin 

 membrane. Plasma sheath-shaped, 

 with firm central nucleus, and 

 numerous vacuoles in the outer 

 part. Pseudopodia long, finger-like. 



P. Patella, CI. and L. Carapace 

 almost bivalvular, interior brown- 

 ish-yellow, without yellowish-gray. 

 0.04 1. 



5. Gen. Arcella, Ehr. Caraj)ace 

 shield-shaped, consisting of two 

 plates, according to Hertwig and 

 Lesser with intermediate hexagonal 

 panel-work, at least, the surface 

 appears to be very finely panelled. 

 Plasma with nuclei and contractile 

 vesicles. 



A. vidgaris, Ehr. Carapace at 



first transparent, later brownish or 



, blackish. Form varies much, at one 



time flat, at another arched, smooth 



or with large facets, imprints, 



corners, or projecting points {A. 

 dentata, Ehr.). The plasma does not 

 entirely fill the carapace, from a 

 central mass filamentous portions 

 radiate to the borders. Nuclei 

 numerous. Pseudopodia finger-like. 

 0.05-0.16 d. Common, among water- 

 plants. 



A. patens, CI. and L., Carter. 

 {Pyxidula opercidata, Ehr., H. and 

 L.) Carapace brownish-yellow, or- 

 bicular, arched above, with small 

 knobs, open beneath, and with a 

 narrow border. Plasma orbicular, 

 with a nucleus. 0.02 d. 



A. hyalina, Ehr., Fres. ( Gromia 

 hyalina, Sch., Dijjiugia enchelys, 

 Schn,, Lecythemnhyalinum, II. and 

 L. ) Carapace almost spherical, 

 transparent, thin but not flexible, 

 with short neck-like projection. 

 The plasma entirely fills the cara- 

 pace. Pseudopodia homogeneous, 

 branched, sometimes anastomosing. 



Q. Gen. Pi-ffl/ugia, Leclerc. Cara- 

 pace made up of diatomaceous re- 

 mains and other foreign particles, 

 cemented or bound together by a 

 membrane. Pseudopodia finger- 

 shaped. 



1). oblong a, L. {D. proteiformis, 

 Duj.) Carapace ovoid, with terminal 

 opening. 0.1-0.25 1. Common, 

 among water plants. 



P. spiralis, H. Carapace retort- 

 shaped, with tangential opening. 

 Surface with undulatory elevations 

 or spiral folds. 0.25 d. or less, l^ot 

 common. 



7. Gen. Echinopyxis, C. and L. 

 {Centropyxis, Stein, Arcella, Ehr., 

 Duj.) Carapace spherical, consti- 

 tuted as in Piflugia, but with hol- 

 low, curved thorns. 



E. aculeata, C. and L. 0.25 d. or 

 less. In ditches, with plants. 



Gregaeina. 



Stein places the Gregarina among 

 the Phizopoda, but others regard 

 them as belonging to another class. 



