10 
EXCURSION TO TENBY. 
In the new tow-net, instead of a bottle an open glass tube 
is attached to the tail end of the net, through which the 
water hows, and the outer extremity of the glass tube is 
expanded to a wide mouth, three inches diameter, across 
which a fine muslin strainer is fixed. This allows a constant 
current of water to pass through the glass tube whilst the 
net is towed along, carrying with it the minute organisms 
that are floating in the water; but whilst the water passes 
through freely, these organisms are all retained in the glass 
by the fine muslin strainer. The net used was a strong, 
coarse muslin funnel 8jft. in length and l|ft. in diameter at 
the mouth, which was kept open by a light brass hoop to 
which the towing cord was attached. An inner shorter 
funnel lift, in length was attached to the same mouth ring, 
ending in an opening about six inches diameter; this 
inner funnel serves as a trap to check the escape from the 
net of any objects that enter it. After towing the net at a 
very slow speed for about ten to fifteen minutes it was drawn 
up, and the glass plunged at once into a basin of water to 
prevent the water sinking down in the glass so low as to 
risk damage to the contained objects by their getting too 
closely packed. The net was then untied from the glass, 
and the contents of the glass poured out for examination. 
Some minor modifications were made in the apparatus in the 
course of the trials, such as dispensing with a cork float 
originally fitted upon the glass tube, and some further minor 
improvements may probably be made as the results of experi¬ 
ence, but the plan proved a thorough success and very 
efficient in working. 
The tow-net collecting was mainly in Tenby Bay, near St. 
Catherine’s Rock, from a rowing boat, and quantities were 
obtained there of Noctiluca miiiaris, the minute globular 
organism that is the most usual cause of phosphorescence of 
the sea; and this phosphorescence was brilliantly shown after 
the specimens were taken ashore, and even remained visible 
in some after bringing them to Birmingham. 
Quantities were also obtained of the medusiform gono- 
zoids of Obelia dichotoma, which are the minute free swimming 
larval state of a polype that in its mature state is stationary 
in a fixed branched form ; these formed very beautiful objects 
for the microscope when in the living state, actively moving 
by the flapping pulsation of the medusa umbrella. The 
delicate and beautiful Cydippe pileus, or Sea-acorn, was also 
found in abundance. 
The larger Medusae, or Jelly-fish, were also caught in the 
tow-net, and sometimes caused trouble by choking up the 
