502 



SYSTEMATIC HISTORY OF THE INFUSORIA. 



seemed terminated by a knob. It is not 

 improbable that Fantotrichum Enchelys 

 (E.) is also a member of this genus. 

 1-1440" to 1-960". Bern. In ponds. 

 — A variety (3/. epilis) occurs, hav- 

 ing the hairs short or actually absent, 

 although covered with little nodules 

 which serve as bases for hairs. Frese- 

 nius has noticed this organism.- He 

 adds, the ends are often pointed. The 

 hairs or bristles are long, and tolerably 

 numerous — as many as 30 have been 

 counted, placed at all parts of the peri- 

 phery. The anterior setiform hairs are 

 most concerned in locomotion j those 



placed laterally either lie along the sides 

 pretty closely, or stand out at a greater 

 or less distance, and appear concerned 

 chiefly in changing the position. The 

 two most in advance seem to have the 

 character of feelers. A clear vacuole 

 was sometimes seen in the middle of the 

 dusky-green contents. A few small, 

 contractile, optically red specks have 

 also been observed. 1-720"' to 1-444"'. 

 Fresenius considers it ought to be re- 

 moved from the Monadina; and Perty 

 is himself imable to decide whether this 

 genus is referable to the Ciliata or to the 

 Phytozoa. 



Genus PLEUROMONAS (Perty) (XYIII. 25).— Body reniform, extremely 

 delicate, small, colourless; filament extended from the concave side of the 

 body, and three times its length. 



Pleuromonas jaculam = Chilomonas 

 ohliqua (?) (Duj.) (x^mi. 25).— Colour- 

 less, transparent, with a few small mole- 

 cules. Movements eccentric, hither 

 and thither in a jerking and leaping 



manner, followed by inter^^als of rest. 

 Very young specimens are round. 

 1-6000" to 1-3160". Bern. In stale 

 water and infusions of Lycopodium 

 seeds. 



Genus SPIPOMONAS (Perty) (XVIII. 24).— Body leaf-like, compressed, 

 rounded at both ends, and roUed spirally on itself longitudinally. 



Spiromonas voluhilis = Cyclidium dis- 

 tortum (Duj.). — Colourless, transparent, 

 smooth, very delicate. Revolves rapidly 

 on its long axis. Not nodular on the 

 margin, like the CycUdium distortimi 



of Dujardin, but is probably (as Dujar- 

 din believes the latter to be) merely a 

 phase of 3Ionas Lois. 1-1800" to 

 1-1300". Bern. In foul water. 



Genus MENOIDIUM (Perty) (XIX. 2).— Body small, crescentic, thicker 

 on the outer or convex margin ; containing internally smaU. molecules and 

 vesicles ; colourless, or occupied with a little chlorophyll. 



Menoidium pellucidum (xix. 2). — j sickle. Movement tolerably rapid, jerk- 

 Eecalls by its figure a little Closteriimi I ing and revolving. 1-670" to 1-430". 

 lunula ', not rounded, but flattened like a { 



Genus CHROMATIUM (Perty) (XIX. 1).— Body extremely small, red, 

 brown, violet, or green in coloiu-, containing in the matiu'e condition some 

 internal vesicles. A motor filament at the anterior extremity (?). Multipli- 

 cation by transverse fission. To this genus Perty would refer the greater 

 part of the Monads described by Ehrenberg which possess a brilliant colour ; 

 and he is in doubt whether they are not all rather referable to the genus 

 Bacterium, as well as the next genus named, i. e. Acariceum. However, he 

 at present retains Chromatium and Acariceum among the Monadina, and 

 establishes two species of the former. 



Chromatium Weissii (xix. 1). — Of 

 a violet or bro"v\Tiish colour, rounded 

 and truncate both before and behind; 

 vesicles -wdthin sharply defined. The 

 3Ionas Ohenii of Weisse is very closely 

 allied, but still more minute. It pro- 

 gresses and revolves rather rapidly, taking 



a straight com'se. The vesicles are not 

 present in very yoimg specimens : they 

 first show themselves as dark points, and 

 afterwards assume the vesicular form. 

 Perty cannot discover the filament de- 

 scribed by Ehrenberg in Ifonas Okenii. 

 Eichwald says of this species that it swims 



