OF THE ENCHELIA. 



615 



into a smaller, rather pointed, anterior 

 section, and a vdder posterior one ; co- 

 loui'less. Extremely delicate; often 

 composed, like many Monads, of only 

 five molecules. Movements of cilia 



sluggish. Swimming often interrupted 

 suddenly by a jerk in another direction. 

 Fission longitudinal. 1-1560" to 1-1320". 

 Rare, among decomposing Confervse. 



Genus PTYXIDIUM (Perty) (XXYIII. 40-42). 

 with several folds. Cilia equal, very fine. 



Ptyxtdium Ovidum — Leucophn/s pi/ri- 

 fonnis (Ehr.). Kolpoda Pyrum (MiilL), 

 which Ehi-enberg cites as synominous, 



-Ovate, pointed in front. 



is more probably an Acomia. Perty dis- 

 covered no food in the interior. 



Genus COLOBIDIUM (Perty) (XXYIII. 45).— ^Tien mature, ovate; in 

 earlier condition, truncate posteriorly — frequently emarginate, — rounded an- 

 teriorly. Cilia in longitudinal rows, those in front longer ; their movements 

 slow. 



CoLOBiDiuMj9e//?/c^V7Mm. — Very trans- 

 parent, colourless or clear gi-een ; move- 

 ments rapid, always rotating. " The 

 longer cilia in front often moved in a 



foot-like 



1900" to 1-600". 

 Bern. 



manner. 

 In tm-f-hollows among Confervse 

 Acomia Vorticella (Duj.) is probably only 

 a variety of this species. 



Genus APIONIDIUM (Perty) (XXYIII. 48, 49).— Rounded ; thicker in 

 front than behind ; rows of cilia few in number. 



Apioxidiuim modestum. — Hyaline, 

 with colom-ed (green or brown) food-par- 

 ticles. Rows of cilia from seven to nine ; 



cilia very fine. A round clear space 

 usually visible posteriorly. Rare. 1-260" 

 to 1-240". 



Genus GASTROCEMETA (Duj.) (XXYI. 18).— Body oval, convex on one 

 side, and hollowed by a longitudinal furrow on the other ; cilia seated in the 

 fmTOW, chiefly at the two ends. 



Gastrochjeta Jissa (xxvi. 18). — Semitransparent, oval, truncate in fi-ont. 

 1-408". In the water of the Seine. 



Genus ALYSCUM (Duj.) (XXYI. 20). — Body ovoid-oblong irregular, 

 surrounded by radiating cilia, and having, besides, a lateral bundle of long- 

 retractile cilia, by means of which it leaps briskly from place to place. 



The single species much resembles Enchelys nodulosa {Paramecium Milium, 

 or Pantotriclimn Enchelys, Ehr.) from which it is distinguished by its retractile 

 filaments. 



Alyscuini saltans (xx^t:. 20). — Colour- 

 less, oblong, rounded at the ends, rather 

 concave along the side bearing the re- 

 tractile filaments, and marked by some 



almost in\-isible 

 1-1300" to 1130" 

 the Seine. 



longitudinal fiuTows. 

 In infusions and in 



Genus UROXEMA (Duj.) (XXYI. 25).— Body long, narrower in front, 

 rather curved; surrounded by radiating cilia, and bearing a long straight 

 cilium behind. 



Uronema marina (xxvi. 25). — Co- 

 lomless, semi-ti'ansparent, nodular, elon- 

 gated; contracted in front; slightly 

 curved, with from four to five slightly- 

 marked longitudinal striae. 1-595". In 

 the MediteiTanean. 



Stein considers this fomi, as in the 

 instance of Cyclidium Gkmcoma, to be 

 merely an embryo of an Infusoriimi, and 

 not an independent species. 



