Tricula, and Cyathopoma milium. 269 
in structure and sculpture; and, as I pointed out, Cyclostoma 
striata, Quoy and Gaimard, referred by Gray and Pfeiffer to 
Acicula, appears to resemble Cyclostoma tersum in many of 
its characters. 
If, as Martens thinks, and I am on the whole disposed to 
agree with him, I was wrong in assigning Cyclostoma tersum 
(or, as I proposed to call it, Acmella tersa) to Acicula, what is 
its generic position? It certainly is no Assiminea; but it may 
be allied ; and if so, it becomes simply a land Rissoid*. It is, of 
course, to be regretted that Major Godwin-Austen did not suc- 
ceed in isolating the very minute teeth of the lingual ribbon and 
figuring them separately, as the presence or absence of basal 
denticles on the central tooth would have aided in deciding the 
question; but since last year I have some further evidence, 
b is in favour of Acmella belonging to this ubiquitous 
amliy. 
Major Godwin-Austen obtained a shell in North Cachar 
which he considered to be a second species of Acmella. It 
was found on wet moss beside a waterfall, in a stream flowing 
into the Jhiri river, at an elevation of about 3000 feet above 
the sea. On examining and comparing the shell, I found it 
emi in a stream at Bheemtal, in Kumaon (Western Hima- 
ayas), at an altitude of 4000 feet above the sea. I have also 
the base of the long filiform tentacles (^ tentaculis filiformibus 
duobus oculos postice prope basin gerentibus ")— precisely as 
in Acicula, in short. Moreover Tricula is evidently a fresh- 
. water shell, living in streams, whilst Acmella is a land-shell. 
* It appears to me far from improbable that Acicula itself belongs to 
the Rissoide. 
f Caleutta Journal of Nat. Hist. 1842. Ann. & Mag. Nat. Hist. Dec. 
dus & Mag. N. Hist. Ser. 4. Vol. vi. 24 
