66 PROFESSOR O. BUTSCHLT. 



occupies only a few minutes, but from the minuteness of the 

 organism the behaviour of the nucleus cannot be observed. 

 No encystation has as yet been noticed in this form. 



Spumella neglecta, Monas neglecta,ci. Clark (loc. cit., 

 p. 138, pi. V, figs. 5, 6), is closely allied to the form just 

 described. 



Spumella vulgaris, Cienkowski (loc. cit.). Biitschli 

 is able on the whole to confirm Cienkowski's description. It 

 is distinguishable from Spumella termo by its very round, 

 and almost spherical shape, and by the absence of the liplike 

 prominence. 



Spumella(?) truncata, Fresenius (" Beitrage zur Ken- 

 ntniss kleinster organismen,^' ' Abhandl. der Senkenberg. 

 Gesselsch. zu Frankfurt-a-M.,^ Bd. ii, pi x, fig. 42), is placed 

 provisionally with Cienkowski's Spumella ; it is a very cha- 

 racteristic organism, and has been well figured by Fresenius, 

 who has described it as Monas truncata in the explanation of 

 his plate, though he has omitted all mention of it in the text. 

 The organism (Plate vi, fig. 3) is very flat, being but thin 

 in proportion to its length and breadth. The contour of the 

 broad side is somewhat oval, although the end bearing the 

 flagellum is cut off to form a sharp slope ; the opposite pole, 

 on the other hand, being either smoothly rounded off or mo- 

 derately pointed. From the higher portion of the anterior 

 end of the body — the sloping portion — proceed two flagella, 

 which are of no great length. In the clear protoplasmic 

 body, near the longer side, is a vesicular nucleus with large 

 dark inner body, which is generally somewhat in front of 

 the centre of the body. The contractile vacuole is on the 

 opposite and shorter side of the body, close to the front 

 anterior border. Immediately in front of the vacuole is a 

 dark band, running nearly parallel to the oblique anterior 

 border, from the shorter side almost to the base of the 

 flagellum. This band is composed of a substance of high 

 refractive index, which on closer scrutiny always appears to 

 be irregularly granular ; and it is sometimes quite apparent 

 that it is made up of a number of highly refracting granules. 

 This band is analogous with the one found by Cienkowski 

 in Spumella vulgaris, and should perhaps be classed with 

 the so-called eyespots in other Flagellata. 



The protoplasmic body contains great numbers of per- 

 manent vacuoles, amongst which the food vacuoles, with their 

 enclosed particles, are so clearly distinguishable that there 



