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13 
WEDNESDAY, FEBRUARY 1roTH, 1904. 
Che Smaller Denizens of our Ponds, 
Lakes, and Ribers, 
BY 
me. MARTIN-DUNCAN, F.E;S., F.L.S. 
R. MARTIN-DUNCAN at the outset of the lecture observed 
I that the gentle art of pond hunting had its attendant risks. 
On one occasion he himself when fishing for a small piece of 
weed, was suddenly and unexpectedly pushed into the pond by a 
billy goat, and came out of it (to quote his own words) *‘ Like unto 
a river god.” The amount of time and patience requisite for 
photographing successfully the appearance and habits of small 
organism was exemplified (1) in the preparation of lantern slides 
showing “Cell conjugation and fusion in Chara” which entailed 
six hours close watching ; (2) in photographing a Rotifer, which 
remained three hours in its glassy like castle before it would show 
itself. ‘The results as displayed by the lantern were much 
appreciated. 
Specimens were then shown of desmids, infusoria and hydras, 
and the curious ‘‘ somersault ” method of locomotion adopted by 
the latter explained. Passing to the Rotifers, Mr. Martin-Duncan 
showed a highly magnified specimen whose constituent cells 
presented the appearance of a pyramid of tiny bricks, and delicate 
tints of different colours, he explained, could be conveyed to the 
cells by merely colouring the creature’s food. Other Rotifers 
with their coronz expanded, some like snowy plumes of delicate 
texture, and others like peacock’s tails set in trellis work, were 
shown, and an explanation was given of the use of the corona in 
securing water fleas, etc., which made up the animal’s food. On 
the subject of water fleas the lecturer explained how certain 
carnivorous plants living in ponds lured them into their bladder 
like body which is provided with a door opening from the outside 
only ; this successfully imprisons the too curious water flea who 
soon perishes and is digested by the juices secreted by the plant. 
Excellent slides were shown illustrating the life changes of 
the dragon fly. Always a voracious feeder, the larva has a heavy 
