224 LORANDE LOSS WOODRUFF 
together with several other forms, which at the present time are 
assigned to other genera. Miiller’s description is as follows*:— 
PARAMAECIUM. Vermis inconspicuus, simplex, pellucidus, mem- 
branaceus, oblongus. 
Paramaecivum aurelia. Paramaecium compressum, versus ant- 
ica plicatum, postice acutum. 
Thus the organism described by Baker® as ‘‘Animalcules in 
pepper water, first sort,” by Joblot® as Chausson, by Ellis’ as 
Volvox terebella, etc., received the name which, in spite of var- 
ious vicissitudes, has come down to the present time. 
The next great student of the lower organisms, C. G. Ehren- 
berg, in the first two of his treatises,’ described several species of 
Paramaecium, and one of these is Paramaecium aurelia. In his 
third treatise® he described still another species which he named 
Paramaecium caudatum.!° Five years later, in 1838, Ehrenberg 
brought out his monumental monograph, Die Infusionsthierchen 
als vollkommene Organismen, and in this work he described these 
two species as follows:!! 
Paramecium Aurelia, Pantoffelthierchen. 
P. corpore cylindrico, subclavato, antica parte paullo 
tenuiore, plica longitudinali obliqua in os multum 
recedens exeunte, utrinque obtuso. 
Paramecium caudatum, geschwinztes Pantoffelthierchen. 
P. corpore fusiformi, antica parte obtusiore, postica magis 
attenuata. 
Thus Ehrenberg described, on the basis of shape and size, the 
two common forms of colorless paramaecia which appear in 
4Page 86. 
5The microscope made easy, London, 1742. 3rd ed., 1744, p. 72, Pl. 7, fig. 1. 
°‘Observat. fait. avec le microscope, Paris, 1754. 
7Observations on a particular manner of increase in the Animalcula of vegetable 
infusions, etc. Phil. Trans., London, 1769. 
8Abhandl. der Akademie d. Wissensch. zu Berlin, 1830, 1831. 
*Tbid, 1833. 
10Whrenberg notes that Herrmann (Naturforscher, 1784) applied the name cau- 
datum to a form which was probably a species of Amphileptus; also Schrank 
(Fauna boica, 1803) used the same name. 
Pp; 350-302. Pl-.39> figs: 6,7. 
