238 ORDER FLAGELLATA-PANTOSTOMATA. 



This species is probably identical with the form described further on under the 

 title of Sterromonas formidna, the second flagellum being of such small size as to 

 have easily evaded the resolving capacities of the magnifying lenses at Dujardin's 

 disposal. At the same time, another species — Oikononas tniitabilis — presents in 

 its free-swimming condition a somewhat similar elongate and constricted contour. 



Monas Oberhauserii, Fres. 



Body cylindrical, rounded at each extremity, hyaline, faintly carmine- 

 coloured, enclosing a variable number of intensely crimson globules ; 

 flao-ellum apparent only through the movements of the animalcule, which 

 are rotatory and tumbling. Length 1-2000" to 1-1150". 



Hab. — Sulphur spring at Frankfort. 



This monad is probably identical with the M. Okeni of Ehrenberg. The 

 M. bipunctata of Fresenius, found under similar conditions, but of smaller size, with 

 an elonf^ate-oval figure, and enclosing one or more red points at each extremity, 

 apparently represents an earlier stage only of this form. The Monas tnmcata of 

 Fresenius, possessing two flagellate appendages, has been selected by Stein as the 

 type of the new genus Gonmno/ias. 



Monas lamellula, Miiller. 



Body minute, compressed, diaphanous, two or three times as long as 

 broad ; flagellum long and undulating ; movements forward in a zigzag 

 manner. Length 1-2000". Hab. — Salt water. 



Originally described by O. F. Miiller as a marine form, but reported to De 

 Fromentel, also from fresh water. 



In accordance with the views of the author, both this and the ten succeeding 

 specific types — embodied by De Fromentel in his ' Etudes sur les Microzoaires,' 

 Paris, 1876, and identified by him on the most slender grounds with the species 

 bearing the same titles first described by O. F. Miiller, Ehrenberg, and Dujardin — 

 might be advantageously consigned to the appended list of " Doubtful species." In 

 no single instance are the characters given sufficiently expHcit for their absolute 

 identification as typical representatives of the genus Monas. 



Monas Kolpoda, Ehr. 



Body convex on one side, flattened on the other, the anterior extremity 

 pointed and bearing a long flagellum ; parenchyma enclosing green 

 granules ; movement oscillating. Length 1-1600". Hab. — Fresh water. 



The above diagnosis, as recently given by De Fromentel, scarcely agrees with 

 the original one of Ehrenberg, who characterizes this species as oval or egg-shaped, 

 having a length of 1-7200" only. 



Monas ovalis, Ehr. 

 Body ovate, colourless ; motion tremulous. Length 1-9600". 



De Fromentel describes this species as differing from M. dcscs only in its absence 

 of colour and the less development of the flagellum. Ehrenberg gives as its habitat 

 the water from the fresh-water mussel, Anodon. 



