350 - Mr. W.H. Benson on new species of Planorbis 
which I compared it, and the slope of the last whorl, underneath, 
towards the penultimate whorl, independently of other characters 
noted, ought to have indicated that the description was quite in- 
applicable to Pl. conveaiusculus, which is wound on a regularly 
increasing open spiral, instead of rapidly increasing in the 
breadth of the last whorl. This rapidity of increase, “but in a 
less degree, is observable in Pl. Cantori. Pl. umbilicalis, moreover, 
could never, by possibility, have been overlooked among examples. 
of Pl. compressus, as Capt. Hutton states to have been the case 
with his Pinjore specimens of Pl. convextusculus. 
5. Planorbis labiatus, nobis, n. s. 
Testa solidiuscula, plano-depressa, nitida, albido-cornea, subdiaphana, 
oblique arcuato-striata, striis remotiusculis spiralibus decussata ; 
apice profunde concavo; sutura profunda; anfractibus 3}, cito 
crescentibus, convexis, ultimo antice majori, ab axe superiorum 
discedenti, rotundato, carina mediana levissima submembranacea 
instructo, infra valde convexo; umbilico subaperto profundiori, 
margine interiori subangulato ; apertura obliqua, cordiformi, tus 
albo-labiata ; margine superiori arcuato, inferiori rotundato. 
Diam. maj. 5, minor 4, axis vix 2 mill. 
Hab. in stagno prope urbem Moradabad. Inter specimina Pl. com- 
pressi (Hutton) detexi. 
This little shell is remarkable for the departure of the last 
whorl from the axis which governs the previous volutions. This 
is especially apparent underneath, where the earlier whorls in 
the umbilicus proceed regularly, the last whorl becoming suddenly 
excentric. The whitish rib within the lip is also a marked cha- 
racter, as well as the proportion of the axis to the diameter. 
6. Planorbis Sindicus, nobis, n. s. 
Testa minuta, perforata, sublenticulari, albida, leevi, subdiaphana, 
supra convexa; spira planulata, apice depresso ; anfractibus 2}, 
ultimo medio obtuse angulato, subtus convexo ; apertura cordata, 
obliqua, margine superiori arcuato, prominente, inferiori recedente. 
Diam. 21 mill.; axis 2 mill. 
Hab. in fluvio Indo, regione Sindica superiori. 
This very distinct and minute species, remarkable, after Pl. 
trochoides, nobis, for its small umbilicus, but of a less trochoid, 
and more lenticular form, I found adhering to the inside of a 
specimen of Paludina Bengalensis sent to me, with other shells 
common to the Gangetic Provinces, from the banks of the Indus 
above Sukkur, by my friend Major FitzGerald, Bengal Cavalry, 
from the expedition which accompanied Shah Shujah under Lord 
Keane to Cabul. No other specimen appears to have been met 
with. 
