CORRESPONDENCE. 
49 
False Light Excluder. — We learn from the ‘ American Naturalist ’ 
that E. Gundlach, of Rochester, New York, mounts his new 2-inch 
lenses with a brass tube | inch long projecting below the front surface 
of the objective, and having a perforated diaphragm at its lower end. 
This cuts off much of the stray light that would otherwise enter, and 
still leaves 1^ inch of working focus. 
CORRESPONDENCE. 
The rate Professor Ch. Gr. Ehrenberg’s Researches on the 
Recent and Fossil Foraminifera. 
(Continued from, page 311, vol. xvii.) 
To the Editor of the ‘ Monthly Microscopical Journal .’ 
Sir, — Recognizing Ehrenberg’s careful research, indefatigable in- 
dustry, and just appreciation of the important bearings and appli- 
cations of the facts he brought to light, Professor W. K. Parker and 
myself * set ourselves to compare and identify, as far as possible, all 
the Foraminifera he had illustrated in his successive publications 
down to 1872 ; and we stated with the highest respect for the veteran 
microscopist, that, though we found it impossible to accept most of 
his specific, and even generic, determinations, yet we felt certain that 
the better Ehrenberg’s work is elucidated and understood, the more 
will his beautiful and lasting illustrations, and his painstaking synop- 
tical registers, advance the progress of biology in its relation both to 
the present and the past. The removal of some obscurity from the 
highly valuable groups of Foraminifera of which he has treated must 
be of use to naturalists and geologists, enabling them to put several 
extensive faunae and local groups into close critical relation with each 
other, and with such as have been observed by others, f 
In 1872 the veteran and almost octogenarian naturalist of Berlin 
laid before the Academy a memoir, with numerous illustrations, as the 
results of his long-continued methodical researches on the micro- 
scopic life of the sea-bottom of all zones ; and especially on its 
relationship to past life, and its bearings on geological formations. 
His chart of the world indicates the localities of 353 soundings in 
the North-Polar (45), North-Temperate (238), Equatorial (58), South- 
Temperate (15), and South-Polar (4) zones, the materials of which 
are described either in this or foregoing memoirs. 
* In the ‘ Annals and Mag. Nat. Hist.,’ Ser. 4, vol. ix. p. 216, &c. 
t After careful comparison of all Ehrenberg's figures of fossil Foraminifera , 
Professors W. K. Parker and T. Rupert Jones have stated that, besides twenty 
undetermined forms, 138 species and noticeable varieties are shown in the 
‘ Mikrogeologie,’ most of which are living at the present day, and eighty-one of 
which had been named by other observers. ‘ Annals and Mag. Nat. Hist.,’ 
March 1873. 
E 2 
