94 
Mr. E. A. Smith on neu ; 
Radula with teeth in seven series (3. 1. 3), central smallest ; 
recurved edge notched at each side, w 7 ith a conspicuous cutting- 
edge ; inner or first lateral obliquely subquadrate, much pro- 
duced at the outer base into a rostrate extremity, with three 
denticles on the recurved cutting-edge ; second lateral larger 
than the rest, oblique, incurved, margin tricuspidate ; outer 
or third lateral narrow, more slender at the base than above, 
curved over towards the adjacent tooth, and wdth five or six 
unequal denticles on the edge. 
Operculum rich brown, horny, narrow, striated externally 
w r ith lines of growth from the paucispiral nucleus, which is 
nearly terminal ; lower surface with a broad glossy band or 
thickening along the outer or right margin, occupying about 
half the surface ; placed transversely across the dorsal part of 
the foot. Length (from a semiadult shell 20 millim. long) 
7 millim., diameter 3^. 
Mr. Gwatkin, who has had much experience, kindly 
examined the radula of this genus, and informs me that he 
is inclined to believe that Nassopsis will find its nearest allies 
in the Cerithiidge, and not amongst the Littorinoids as I had 
suggested. It also seems to me to bear considerable resem- 
blance to Planaxis . 
In general construction the operculum is very like that of 
many species of Melania , but the peculiar solidity of the shell 
and the slight notch at the base of the columella, besides 
certain differences in the radula, may be sufficient to separate 
this and allied species as a distinct group. 
Syrnolopsis ( Anceya ) Giraudi , var. 
A single specimen, kindly submitted to me for examination 
by Mr. S. I. Da Costa, agrees in most respects with M. Bour- 
guignat’s description. It differs, however, in colour, being 
of a red tint with a white zone around the middle of the 
whorls. It does not exhibit the palatal lira in the aperture, 
but these may be too far within to be visible. In adult speci- 
mens of Syrnolopsis lacustris the lira cannot be seen until the 
lip is broken away to some extent. As far as I can discover 
the only distinction separating Anceya from Syrnolopsis is 
one of sculpture. The type of Syrnolopsis has smooth whorls, 
w r hereas that of Anceya is longitudinally costate. If sculp- 
ture be admitted as a generic character there is no reason wrhy 
Syrnolopsis carinifera should not be regarded as the type of a 
third genus characterized by spiral ridges. The general form 
of the aperture is the same in all three forms ; it is slightly 
oblique and has an upper and basal broad sinus or slight 
