104 LAND AND FRESHWATER 
pointed lobe over the mucous gland at extremity of foot. Mantle 
slightly reflected over the margin of the peristome, with two tongue- 
shaped expansions, which the animal expands and contracts. This 
shell I found in a semifossil state embedded in the deposits of 
tufa in crevasses of the limestone. 
The colour of this snail distinguishes it at once from the species 
of the Gangetic delta. 
The specimens above described were shown by me to Capt. T. 
Hutton, and he at once advised my noting the colour of the animal, 
and gave me the title petrosa. Captain Hutton, some years after, 
presented me with all the shell-pamphlets he possessed, which had 
been most of them given him by Mr. W. H. Benson. In one (Ann. 
& Mag. Nat. Hist. Sept. 1848, on p. 163) I find the following note 
in Benson’s handwriting :—‘ Hutton’s original H. petrosa was from 
Mirzapur. Query, is it identical with the mountain form from 
Mussoorie which he now refers to that name?” 
To this again is appended a note by Hutton, as follows :—“ With 
reference to Benson’s query as to whether the Mirzapur shell was 
the same as that of Mussoorie, I answer certainly not, as he must 
have known, having both species before him; the Mirzapur shell 
was Nanina vitrinoides of Deshayes, the other Nanina petrosa (nob.), 
the name being altered by Benson’s advice. When I first found J. 
vitrinoides, | knew nothing of species and recorded my discoveries 
haphazard. 
** Benson thought the Mussoorie shell a mere variety of NV. vitri- 
noides ; but as we differed he recommended my giving it a name, 
which I did, and I still regard the species as distinct. (Signed T, H.)” 
We now know how it was that between them the title petrosa was 
altered. The Mirzapur form known to Benson as vitrinoides must 
retain Hutton’s original name petrosa, and Mr. Nevill has since indi- 
cated and described the “Masuri”’ species under the distinctive 
name prona. The exact range of petrosa has yet to be defined (vide 
my remarks on the species from Rajmahal). 
The specific designation prona may have been taken from a MS. 
name of Mr. W. T. Blanford’s or vice versa; for in his collection 
and in his MS. list of it prona is the name given to the species 
from Parisnath, which is, I find, also distinct, and I have therefore 
had to describe it under the title jainiana. 
Original description :—‘ Shell small, of the same group as J. 
petrosa, Hutt. &c., but with closer-wound whorls; itis a form which 
apparently is widely spread throughout the North-western Hima- 
layas, as the Museum possesses numerous specimens from Simla, 
Masuri, Naini Tal, and Sahdrunpur ; two specimens found by Colonel 
Godwin-Austen in the Dafla Hills also apparently belong here*. A 
very similar small form, but I think specifically distinct, is also found 
in the Bombay Presidency. Dr. Stoliczka’s specimens from Murree 
are all young or in bad preservation ; I have therefore determined 
on not naming the species from his Murree specimens, but take as 
my type the common North-west Himalayan form, the animal of 
* These I have not seen, and I doubt the identification._-G. A. 
