STUDIES ON SOME FLAGELLATA. 

 BY E. PENARD. 



While studying Infusoria, in the neighborhood of Geneva, 

 Switzerland, during the years 1914 to 1918, I often happened to 

 meet with particularly interesting Flagellata, and sometimes inter- 

 rupted my ordinary work to study some of these organisms. The 

 results of these investigations appear of sufficient interest for pub- 

 hcation, and it is a particular pleasure for me to make them known 

 here. The species to be discussed are: Pteridomonas scherffeli 

 Lemm., Dimorpha tetramastix sp. n., Dimoryha monomastix sp. n. 

 Bicoeca exilis sp. n., Histiona campanula sp. n., Salpingoeca poly- 

 gonatum sp. n., Salpingoeca lepidula sp. n., Ckrysamoeba radians 

 Klebs, Chrysopyxis bipes Stein, Hyalobryon ramosum Lauterborn, 

 Cryptomonas ovata Ehrenberg, Astasia mohilis (Rehberg) Alexieeff, 

 Euglena pseudomermis sp. n., Trentonia flagellata Stokes. 

 Pteridomonas scherffeli Lemm Plate V, figs. 1-3. 



Though the description of the genus Pteridomonas dates back as 

 far as 1890 (Penard, 28), the first concise diagnosis which we possess 

 is due to Lemmermann (24), and I can do no better than to repro- 

 duce it here, at least in its most important points: 



Pterdomonas Petard. Cells naked, mostly stalked; 1 flagellum, 

 and rarely, besides, 2 slowly vibrating accessory flagella. At the 

 base of the flagellum, a crown of fine radiating pseudopodia. One 

 or two contractile vacuoles. Nucles with distrinct caryosom. 

 Multiplication unknown. Food taken by the pseudomopodia, or 

 by means of special food-vacuoles. Movement freely rotating, 

 swinging, or by sudden leaps backward, due to the contraction of 

 the stalk. ' 



As for Pteridomojias scherffeli, which was found by Scherffel in 

 Hungary, then by Lemmermann at Bremen, Germany, its specific 

 characters are indicated as follows: ''Cells generally longer than 

 broad, in optical longitudinal section rounded with 5-6 angles. 

 Stalk long and fine. Nucleus near the base of the flagellum. Be- 

 sides the anterior crown of pseudopodia, some lateral radiating 

 pseudopodia." 



This Pteridomonas scherffeli was found in great quantities in 

 the month of September last (1918), among the decaying leaves 

 that filled the bottom of a pond, at the Ariana Park, near Geneva. 



(105) 



