- 862 Mr. H. J. Carter on Spongilla. 
But the language which it would be necessary to employ 
would resemble so closely what has been used above touching 
Rhacodes and Armadillidium, that it might be wearisome to 
your readers. The qualities of Dr. Gerstacker’s work are 
too well known to make it necessary to conclude with compli- 
ments as a set-off against fault-finding. 
Croydon, 
October 4, 1882. 
XXXVIII.—Spermatozoa, Polygonal Cell-structure, and the 
Green Colour in Spongilla, together with a new Species. 
By H. J. Carrer, F.R.S. &e. 
[Plate XVI.] 
As time progresses so experience throws light upon the 
nature of objects previously unrealized, and thus, much of 
what was simply (if correctly) recorded years before may 
derive explanation from more recent discoveries that have 
been made public. 
When I was studying the freshwater sponges of the tanks 
in Bombay, about 1850, Lieberkiihn was engaged with those 
from the river Spree, at Berlin; and although we were both 
working on the same subject, our facts were differently 
handled; for while Lieberkiihn had for friend and adviser 
Johannes Miiller at Berlin, I not only had no one of the kind 
at Bombay, but at that time was beholden to others for the 
loan even of a microscope, so that literally I then felt that 
all I could do was to describe and delineate faithfully what 
came before me both for text-book of reference and publica- 
tion. 
Yet was IJ not altogether without assistance and advice; for 
at University College, London, I had been educated in part 
under my kind and dear friends Professors Grant and Sharpey, 
whose exemplary love of truth stood by me when alone, and 
has ever kept me in the path of fearless accuracy. 
For the purpose of recording my observations, I kept a 
“Journal,” in which was not only described, but delineated in 
colours, every thing that appeared to me worth recording ; so 
that after many years this journal, still continued, often fur- 
nishes me with the means of confirming and realizing disco- 
veries which I myself had long since unwittingly made— 
although often imperfectly, from the limited power of my 
microscope. 
Thus Mr. Saville Kent, in his excellent ‘ Manual of the 
