I0o THE MICROSCOPICAL NEWS. 
the receptacle without any perceptible covering, and are called 
naked, whilst in others they are covered while young with a 
membraneous cover, called an zwdusium, which bursts as the 
spore cases grow, and is either cast off or pushed aside. Whena 
similar membrane is placed beneath the sorus it is called an 
involucre, but this is seldom met with. 
These indusia, which are either sfectal, accessory, or universal, 
take various and beautiful forms. 
After Mr. Harvard had concluded his paper the President of 
the Society, Mr. C. L. Jackson, F.R.M.S., F.C.S., F.L.S., gave an 
interesting lecture on “Fish Scales,” illustrated by the oxy- 
hydrogen light. 
The lecturer drew attention in the first place to the difference 
between the scales of reptiles and fishes, the former being merely 
folds of the skin, while the latter are bony, or bony plates embedded 
more or less in the skin. A large number of sketches of the forms 
of fish scales were thrown on the screen by the oxyhydrogen 
lantern, and the different varieties were described, notice was 
particularly given to the curious fact that in geological times the 
scales of the fishes, which then existed, were massive armour 
plates strongly interlaced, or even dovetailed together. We have at 
present very few species of fish carrying such a covering. The 
variations in the form of scales under the influence of artificial 
culture was illustrated, and at the close of the lecture there was an 
interesting discussion on the use of scales to the fish, and great 
admiration was expressed at the wonderful beauty, and great 
variety of their forms. A large number of specimens were 
exhibited under the microscopes, and at the close of the lecture 
Mr. Jackson exhibited some very beautiful specimens of em- 
broidery in fish scales. The lecturer concluded, after acknow- 
ledging the kindness of Mr. Sachs, of London, in assisting him 
to procure specimens, &c., and of Mr. Pennington and Mr. Russell, 
in assisting him with the preparation of the lantern slides and the 
manipulation of the lantern. 
DIVISION OF LABOUR AMONG MICROSCOPISTS. 
By Pror. J. M. MANSFIELD. 
A paper read before the American Society of Microscopists, Chicago Meeting. 
| pea is now no systematic, conscious oversight in the multi- 
tude of researches in microscopy. Each man, moved by the 
impulse of discovery, pushes out in whatever direction his immedi- 
ate surroundings or accident may suggest. He could often just as 
