86 Mr. H. J. Carter on Freshwater Rhizopoda 



many specimens of A. oculata, Stein (mihi), in aggregated 

 masses of nine or more individuals held together by their united 

 sarcodes, in the midst of which were spaces containing large 

 cells of homogeneous, semiopake, colourless matter, like those 

 of the marine species figured by Stein : but of this gregarious 

 form I hope to write more hereafter. 



Figs. 23 & 24 represent yet two more species (or, perhaps, 

 varieties) of ^. Eichhornii. In both, the plastic investing mem- 

 brane is seen to be carried out in an arachnoid form beyond the 

 body; but in fig. 23 only was the nucleus and a portion of crude 

 food observed ; while in the two specimens of fig, 24 seen (one 

 with and the other without the arachnoid expansion) there was 

 nothing, according to my notes, but colourless granules. Hence 

 this, with the capitate tentacula, makes it look like Acineta; but 

 its general appearance, and the probability that the hastiform 

 extremities of the tentacula are merely accumulations of the 

 plastic investing membrane, incline me to the side of Adino- 

 phrys. 



AcANTHocYSTis, uov. gen. 

 Acanthocystis turfacea, n. sp. PI. II. fig. 25. 



This species is described at p. 263 of the 'Annals ' (ser. 3. 

 vol. xii.) and fully illustrated in PI. II. fig. 25, &c., while a detailed 

 account of the illustrations will be found in the * Explanation ' 

 to the plate. I have nothing more to add here to my description, 

 except that, if A. viridis, Ehr., be A. brevicirrhis, Perty, coloured 

 by chlorophyll, as suspected by Claparede and Lachmann (p. 452), 

 then the description of the latter given at p. 450 makes it also 

 very like Acanthocystis turfacea ; but the two descriptions will 

 be found to be by no means identical. 



EXPLANATION OF THE PLATES. 



N.B. The tests in Plate L figs. 1, 5, 7-11, 125-, 13/, 14 a,g, i,l,m, 

 and 26, and in PI. H. figs. \5 g, 16, 17, 18 d, e, and fig. 21, are all drawn 

 upon the scale of ^th to ^ H^th of an inch, in order that their relative sizes 

 may be seen. 



AH the figures are, of course, more or less diagrammatic, for the purpose 

 of description ; but nature has been departed from as little as possible. 



Plate L 



Fig. 1. Difflijgia pyriformis, Perty (mihi), magnified: a, test; b, grains of 

 hyaline quartz ; c, pseudopodia ; d, diaphane ; e, dentiform at- 

 tachments of the same to the test ; /, sarcode ; g, chlorophyll- 

 cells ; h, food ; i, nucleus ; k, k, vesicula; or contracting vesicles ; 

 I, acuminated variety of test ; m, pyriform variety. 



Fig. 2. The same, spheruliferous nucleus of: a, nucleolus; b, imaginary 

 section of the same ; c, central cavity ; d, layer of nuclear proto- 



