Incted as a fretting powder, working onder the foot. 
This theory r*^presented a mode of working more in 
Hccordance with lb«t of many mollascM, as the 
S >Ien, Carduim, Mactra, Dentaliam, Ac, which 
rapidly burrowpd holes in mnd and sand by the paction 
of the" foot. Mr. Jeffries concluded his paper with some 
remarks upon the geological importance of these rock-boring 
moUusca, and reflections upon the wisdom of the Creator 
suggested by the contefoplation of the perfection ©f his 
works. The paper wan illastrated by a collection of every 
British species of Pholas, in sUn, and of many other rock- 
boring mol loses. 
In the discussion which ensned, Mr. Leipner reminded the 
society of Mr. Graham Ponton's paper, read in March last, 
when the author mentioned rock-boring as one of the func- 
tions of the foot of the Conchifera. Mr. Sanders and Mr. 
Carpenter albided to the nseof the siliceous tongue possessed 
I bv many Gii^teropods as an instrument of perforation. Mr. 
Stoddart, Mr. Lobb, and others, also took part in the 
I discussion. 
The second paper was by Mr. Henry Brightman, on the 
application of the Photographic printing process for produc- 
ing copies of botanical and other specimens. To lay plants, 
Aic, upon prepared paper, and expose them to sunlight, was 
a method which had been freqnetitly practised, but the 
pictures so obtained were, technically, negatives, the repre- 
sentation of the obiect being white, on a dark ground. It 
occurred to the author that if these could be rendered trans- 
parent positives might be printed from them. He found, 
however, that this could be readily done without any pre- 
vious preparation of the negative, and be exhibited a number 
of very beautiful photographs produced in this way of 
ferns, leave*, and even a butterfly's wing, showing the wide 
applicability of the process. Mr. Brightman then described 
the proce.es in detail ; for the negatives the albomenised 
paper should be as thin and free from grain as 
possible, and sensitised by floating on a 60-grain so- 
lution of nitrate of silver. An ordinary print- 
ing frame was used, but a very long exposure was 
i requisite, especially for positives, and this constituted the 
chief objection to the process where many copies were 
I required, as for illustrating a book. The toning bath con- 
tained half an ounce of acetate of soda to one pint of water, 
and one grain of chloride of gold for each sheet toned. The 
picture was lixed with hyposulphite of soda (eight ounces 
to the pint), and well washed with water. 
Much conversation then took place on this paper, in the 
course of which Mr. Beattie urged the employment of waxed 
paper, instead of albumenised, as likely to give a more trans- 
parent n^ative, and spnk« of the applica^on of carbon 
printing to this process. Mr. Brightman suggested the use 
of a green instead of a black pigment in that method, to 
give the natural colour fi the plant. Mr. Ravis mentioned 
the expense of the silver process as an obstacle to its em- 
ployment on a large scale. The possibility of printing 
negatives on dry collodion or taunin plates was suggested. 
Mr. J, W. Clarke exhibited a beautiful case of living rep- 
tiles, containing examples of the orders Ophidia (snakes), 
and Sauria (lizards) in the class Reptilia, and of the class 
Batrachia. The green lizards he had kept for many years, 
and fed them on any kind of living insect; they only par- 
tially hybernated in confinement. The German salamanders 
also readily lived in confinement. The sloe or blind worm 
was not really a snake but a Siurivin, as it possessed rudi- 
mentary legs under the skin. Mr. Leipner, in making some 
: remarks upon these animals, referred to the new species of 
British snake, Coronella, so named from the emerald green 
crown on its head, and expressed a desire to obtain a 
specimen. Mr. Clarke said that donbtlfss many had been 
destroyed, being mistaken for adders ; tbeir bite was 
not poisonous, and they could be domesticated, but would 
only eat small lizards in confinement. Mr. Sanders referred to 
, the marks opon slabs of stone found in Cheshire as having 
j been probably produced by snakes wriggling upon soft mud, 
I which was afterwards consolidated. 
