QE EE 

1923.] Zoological Results of Expedition to Yunnan. 409: 
sis a small. conoidal, comparatively thin-shelled form 
with the spiral ridges indefinite and variable, but never prom- 
inent and the mouth of the shell relatively Jarge.’ The shell 
when fresh is of a bright olive-green colour, rut with 
a greyish tinge and with occasional black vertical strea 
e tvpe specimens (No. 2321. /nd. Mus.) are from Riley: 
su in Amoy, but the form seems to be common in the mountains 
of western Yunnan. It was collected by the Perey Sladen 
Trust Expedition at several places on the upper Mekong and 
the upper Salween between the Burmese frontier and Tali-fu 
at altitudes between 6,000 and 7,000 feet. and occurs both in 
rice-fields and in streams, the latter probably sluggish. 
Form limnophila Mabille. 
(Plate 17, Fig. 4). 
1886, — limnophila and V. seei — berate Bull. Soc. Mai. 
France, III, pp. 72, 74, Plate II, Fig 
This hoe is dining dished from the Pini minor chiefly by 
its larger size and much thicker shell. The size of the mouth is 
variable. The series before me from Erh-hai offers a complete 
transition between Mabille’s two supposed species. but his figure 
of limnophila is of an exceptionally large shell and I have seen 
none so big. The shells in our collection are all from raised 
beac 
his form is apparently endemic in Erh-hai but I know 
nothing of its ecology; some specimens of dispiralis from a 
swampy lake north of Ho-chang approach it closely 
Form dispiralis (Heude). 
(Plate 17, Fig. 3). 
1890. oe Ase gg Sor gos * Mém. Nat. Hist. Emp. Chinois, I, 
175, e XXIX, Fi 
This is a ee elongate, acuminate, more or less conoidal 
form sada a thick shell. Both the outline of the aang and the 
doubtless toa a the name. The s hell is less cylindrical 
than that of quadrata (s,8.) and has the whorls more convex. 
commo 
H ull says that this form occurs in the waters of 
oe Pes an. ean specimens were obtained by 
(some of these have e periostracum still present in places) 
and also (fresh) ie — swampy lake north of Ho-ching on the 
