PROCEEDINGS OF THE PERTHSHIRE SOCIETY OF NATURAL SCIENCE. 
145 
from whom Mr Knox bought it. Mr Knox kindly sent 
the volume for my inspection a short time ago ; and, 
though naturally reluctant to part with any of the contents 
of the interesting volume, he has consented to present this 
specimen of Garex ustulala to our Herbarium. The very 
complimentary terms in which he has made the gift are 
too personal (to me) for me to repeat. As, however, his 
letter is an item in the history of the specimen, I have 
attached it to the same sheet. I think a very hearty 
vote of thanks is due to Mr Knox for his gift, especially 
when we consider that, as specimens cannot be pur¬ 
chased now, it forms an invaluable acquisition to 
our collection. I take this opportunity of exhibiting 
another of Don’s Perthshire discoveries, a specimen of 
which is in the volume mentioned above, and which I now 
show you. This is a grass which Don found on Ben 
Lawers, and which he thought was an undescribed species, 
and called Triticum alpinum. Visitors to Ben Lawers 
seem generally to have overlooked it, but that it is still 
there is proved by a specimen I have seen, and which was 
gathered by Mr Cosmo Melvill in 1878. Mr Melvill had 
not, however, seen Don’s specimens, and did not identify 
it as the same plant. This I was enabled to do when Mr 
Knox sent me Don’s volume. The plant, however, is not 
a distinct species, but a variety of one of the lowland 
grasses. Most botanists, following Mitten, consider it to 
be a variety of Triticum caninum —the var. biflorum Mit¬ 
ten. Hooker, however, who had seen a specimen, thought 
it belonged to T. repens; and a careful examination of 
Don’s and Mr Melvill’s specimens leads me to think that 
it is almost identical with the var. barbatum of T. repens. 
The plant can probably be found again, and a careful 
study of it on the spot will probably settle any doubtful 
points with regard to it that still remain. 
Dr F. B. White also exhibited an orange (which had 
been sent by Dr Baird) showing a smaller orange in the 
centre. 
Mr Henry Coates exhibited specimens of Helix nemo- 
rails, and read the following notes:— 
The shells which are laid on the table to-night were handed to 
me some time ago, along with others, by Dr Buchanan White, to 
name and mount for the Museum. They were gathered in the 
summer of 1869 or 1870 in the neighbourhood of Balgowati by a 
gardener or keeper there, by whom they were given to Mr J. 
Dawson for the Society. 'They all belong to the species Helix 
ntmoralis L., the “ Common Banded Snail,” and are remarkable 
for the extraordinary amount of .variation which they present, 
and which I have not seen equalled in a series gathered within 
so comparatively small an area. I have submitted them to Mr 
J. W. Taylor, of Leeds, editor of the Journal of Conchology, who 
lias kindly sent me some notes upon them. I have also compared 
them with his list of varieties in that journal and with Jeffrey’s 
descriptions, and have made out nine varieties, besides the type. 
It may seem at first sight a mere waste of time to divide a species 
into a number of groups differing only in the colour, banding, 
shape, and size of the shell, and to give to each of these a distinct 
name; but we must bear in mind that from a biological point of 
view, it is always of use to record variations of species, and, in 
the present instance, the interest arises in all these varieties 
having been found in one locality. The unnecessary multiplica¬ 
tion of varieties, and also of species, is certainly to be deprecated; 
but when a variety with well-marked characters has been de¬ 
scribed, we may learn something regarding the history of the 
species by tracing the occurrence of such a variety in different 
parts of the country, and noting the effect of surrounding condi¬ 
tions on its distribution. For this reason, I have, in arranging 
the land and fresh-water shells for the Museum, represented as 
many well-established varieties as possible, but much yet remains 
to be done in this direction in working up the Mollusca of our 
district. It has long been a matter of controversy whether the 
forms referred to in this note should all be included in one 
species, or divided into two. Of the two authorities already 
mentioned, Dr J. 6. Jeffrey adopts the former view, and Mr J. 
W. Taylor the latter. As I have adhered to Jeffrey’s arrange¬ 
ment throughout, I have done so in this instance as well. I 
think his arguments for making one species only are conclusive, 
for the animal is practically the same in both forms, and the 
shell appears almost or completely to merge from the one into 
the other. 
I shall briefly describe the varieties comprised in the series. 
The typical form (sometimes called quinquifaciata) has a 
yellow or chocolate ground, five brown bands, and a brown lip; 
and measures from f-inch to 9-10th-inch in diameter. The first 
variety, hortensis Mull., is that for which the dignity of a species 
is claimed. The shell is rather smaller and more globular than 
in the type, the ground a dull lemon yellow, and the lip white. 
Var. minor Moq. possesses the characters of the preceding variety, 
but with a smaller shell, measuring about 5-16th-inch. Var. hor- 
tensis-lutea Moq. also resembles liortensis, but is destitute of bands. 
This is a very beautiful variety, with a bright yellow shell and 
white procelain lip, and is by no means common. Dr Buchanan 
White has handed me some specimens for the Museum, gathered 
by himself in Glen Tilt at an altitude of 1600 feet. Vars. libel- 
lula Risso. and castanea Moq. have a ground colour of yellow 
and chestnut respectively, a brown lip, and no bands. Var. 
hyalozonata, Taylor, has the bands translucent. There is a 
single specimen of this curious variety in the Balgowan series, 
which has the mouth contracted, lip white, second whorl very 
large, and spire rather produced. Var. cincta, of French 
authors, is encircled by a single narrow band on the centre of 
the whorl. This is the central of the five bands, the four lateral 
ones being absent. The lip is brown. Var. coalita, also of 
French authors, has two or more of the bands coalesced together, 
with the lip also brown. Mr Taylor describes in the Journal of 
Conchology (vol. iv. p. 46) a formula by which the variations of 
banding may be very conveniently expressed. The bands are 
numbered 1, 2, 3, 4, and 5 respectively, commencing from the 
