332 MR. G. 8S. WEST ON SOME BRITISH 
colour, and habit. G. fluviatilis, Duj., was found among Potamo- 
geton in the R. Seine, and has an oval shell of much larger size. 
G. terricola, Leidy, occurs on the ground amongst moist mosses, 
and is also a much larger animal. 
A species found amongst Ceratophyllum and other water- 
plants, and described as G. granulata by Schulze (in Archiv fir 
mikr. Anat. 1875, xi. p. 117, t. vi. ff. 5, 6), appears to me to be 
hardly distinguishable from G. fluviatilis, Duj. 
The green colour of G. stagnalis is due to the presence of more 
or less diffuse chlorophyll in the protoplasm of the body. This 
has most likely been acquired by the animal whilst feeding on 
the numerous small green alge with which it was associated. 
The protoplasm, which is poured out from the mouth of the 
shell in quantity, has a dull and somewhat translucent appear- 
ance, and exhibits no visible granulation. Nor is a continuous 
streaming movement to be observed in the pseudopodia, the 
general movements of which are very slow. 
Fam. AMPHISTOMINA. 
Gen. Dirptopnurys, Barker. 
52. DipropHrys ArcHerit, Barker, in Qu. Jour. Mier. Sci. 
1868, p. 123; Hertwig § Lesser, in Archiv fur mikr. Anat. 
1874, x. Suppl. p. 189, t. ii. f. 9. 
In stagnant ditches, near Brigg, Lincolnshire. In bog-pools, 
Thursley Common, Surrey. Lough Gatny, Co. Donegal, Ireland. 
All the specimens observed were small in size, and without 
exception were solitary individuals. The average diameter of the 
body was 14 yu. 
Gen. AMPHITREMA, Archer. 
58. AmMPHITREMA Wrieurranum, Archer, in Qu. Jour. Mier. 
Sci. 1867, vii. p. 4; 1870, x. p. 122, t. xx. ff. 4, 5. 
This is evidently a rare species of Rhizopod. I have only 
obtained it once, from Llyn Liydaw, Snowdon, N. Wales. Length 
of shell 604; diameter of shell 36 p. 
Some shells of an amphistomous Rhizopod were observed from 
near Recess, W. Ireland, which probably pertained to this genus. 
The shells were chitinoid, yellow in colour, and each aperture was 
‘situated on a slight protuberance. No living animals of this 
form were observed. 
