Royal Society. 257 
vol. x. No. 43) ; and, thirdly, by myself in damp earth of a field 
Opposite my house, and also under decaying fungi in the 
the name of Geodesmus bilineatus. T am in, i 
quite distinct from the Planaria terrestris of Dugès (Annales 
es Scien vol. xx.), since in England by at least 
. e 
bericht der Schles. Gesellsch. f. vaterl. Cultur, 1866, pp. 61- 
64), but I have had no access to it. Would you kindly give 
In your pages an abstract of that memoir? 
I remain, Gentlemen, . - 
Yours faithfully, 
W. Hovaurox, M.A., F.L.S. 
Preston Rectory, Wellington, Salop. 
August 12, 1870. 
PROCEEDINGS OF LEARNED SOCIETIES. 
ROYAL SOCIETY. 
April 28, 1870.—Dr. William Allen Miller, Treasurer and 
Vice-President, in the Chair. 
* On an Aplanatic Searcher, and its effects in improving High- 
power Definition in the Microscope.” By G. W. Rovsrow-Proorr, 
.à., M.D. ntab, M.R.C.P., F.R.A.S., F.C.P.S., formerly 
Fellow of St. Peter’s College, Cambridge. 
The Aplanatie Searcher is intended to improve the penetration, 
amplify magnifying-power, intensify definition, and raise the objec 
tive somewhat further from its dangerous proximity to the delicate 
covering-glass indispensable to the observation of objects under very 
high powers. 
construeted by Messrs. Powell and Lealand. 
à periments having been instituted on the nature of the errors, 
it was found that the instrument required a better distribution of 
Ann. & Mag. N. Hist. Ser.4. Vol. vi. 17 
