102 LIVERPOOL BIOLOGICAL SOCIETY. 
in the apparatus to be described in the sequel. A different 
system has however, been utilised by Professor Chun. * 
His net is, in its essence, similar to my own, but it is 
opened and then closed again by the action of a fan which 
revolves as the apparatus is drawn through the water. 
Thus the whole has to be drawn for a certain distance 
before the net will open, and it will shut again after, and 
only after, a certain additional distance has been traversed. 
In the hands of its inventor this net has made valuable 
additions to our knowledge, but it is the operator who is 
dependent on the net and not the net on the operator. 
During the past summer, when engaged in the Firth of 
Clyde in superintending the operations of dredging and 
trawling in the “ Medusa,” my attention was continually 
directed to the solution of this problem, and the results of 
my experiments are detailed in the present communication. 
I may add that at that period I was only acquainted with 
the apparatus of Professor Pavesi and of Mr. Turbyne. 
DESCRIPTION OF THE APPARATUS. 
The apparatus, which is exhibited this evening, may 
be conveniently considered in three portions—(1) the net- 
frame, (2) the lock, (8) the messengers. 
1. The Net-Frame. 
The net itself is simply a conical bag either of muslin 
or of silk bolting cloth, which has the advantage of being 
very much more durable. It is attached to a brass ring 
(fig. 2, a. b.) which in the experimental apparatus is two 
feet in diameter, and consists of two semi-circles hinged 
together in such a manner that they can fold against 
another semi-circular piece, and so close the net. This 
* Bibliotheca Zoologica, Heft 1, pp. 8—6, pl. i., 1888. 

