336 W. ARCHER. 



belo ng to the organisation of the species as do the same in 

 any other habitually chlorophyll-bearing form, such an 

 Acanthocystis turfacea, Raphidiophrys mriclis, &c., and are 

 not at all merely due to incepted food of algal nature. 



The place of this form may probably be beside Arcella ; 

 as to the flexibility of the test, that characteristic is possessed 

 by the test of Pseudochlamys. The pseudopodia, however, 

 are thin and slender, terete and pointed, but, as is well 

 known, those of Arcella are much more like those of Dif- 

 flugia. Still, Hertwig and Lesser are more inclined to keep 

 their genus apart from Monothalamia, on account of the 

 great mobility of the body-form. 



A pretty similar account of this form is likewise given by 

 si-ilhard Schulze.^ This author does not concur in the 

 opinion that pseudopodia can at any time be protruded 

 through the investing coat, but that such may not, at least 

 sometimes, take place seems to be contradicted by Hertwig 

 and Lesser's figure already cited.- Schulze also corrects my 

 error as to the seeming envelope of sarcode matter, which 

 (as mentioned) is, in fact, only the broadened out " oral " 

 part of the structure. Schulze has not found the pilose 

 form ; he regards the chlorophyll-granules sometimes seen 

 as due to incepted (algal) food. As mentioned, I cannot 

 concur in this view. 



R.HIZOPODA Monothalamia amphistomata. 

 Ditrema Jlavum, n. s., Archer (PI. XXT, fig. 9). 



About the size of Amphitrema Wrightianum, this pretty, 

 and though seemingly widely diff'used, still very rare rhizo- 

 pod, is quite diff'erent in form and colour therefrom, whilst 

 it must be held as essentially (generically) distinct, the test 

 being a pure secretion-product, the form repudiating any 

 employment of foreign particles in its construction. It is 

 compressed, broadly elliptic in the broad or usual view. The 

 opposite sides in this view for a time parallel or gently concave 

 at the middle, becoming gradually merged in the broadly 

 rounded ends, in each of which occurs a rounded very 

 sharply bordered " mouth," a slight rim projecting inwardly, 

 the whole looking as it were like a perforation cleanly and 

 sharply " drilled " through. The test is of a yellow colour, 

 the margins of the opposite apical openings approaching to 

 a reddish tint (probably because they are somewhat thicker), 



1 E. Schulze: " Ehizopodstudien " in Scliultze's ' Arcliiv f. Mikr. Anat.,' 

 Bd. xi, p. 337, t. xix, f. 1—5. 

 - Loc. cit., t. ii, f. viii, A. (See our reproductiou thereof, fig. 8.) 



