102 PBOCEEDINGS OF THE QUEKETT MICROSCOPICAL SOCIETY. 



a dark-background, it will be seen to consist of alternating 

 dense and semi-transparent rings. The dense part is the spring 

 and summer growth when food is plentiful, and the less dense the 

 winter growth, when in some cases the fish feeds very little, 

 or even for a week or two ceases to feed. The age is found 

 by counting these rings of seasonal growth. Scales may be 

 used in the same way, but they are apt to be damaged and 

 abraded, so that the rings are more difficult to count. 

 Photographs of various marine worms were next shown, in- 

 cluding the lug- worm, which is used as bait, and the sea-mouse, 

 which is much eaten by cod-fish, in spite of its bristles. Mr. 

 Martin Duncan had investigated the movements of the legs of 

 the many-footed worms in walking by means of cinematograph 

 pictures. Photographs of several tube-building worms were 

 shown. Various materials are used, and each piece is passed 

 to the mouth in the Lanice conchelegia before being placed in 

 position. Owing to the difficulty of obtaining cocaine for 

 narcotising, the lecturer had tried menthol crystals, which he 

 had scattered on the surface of the water containing the 

 creatures required to be narcotised. In the case of sea 

 anemones the method was successful, but slow, taking twelve to 

 twenty-four hours before they could be plunged into the killing 

 fluid. Photographs were shown of some hydrozoa, and a very 

 fine photograph of some living sea-anemones. The next slides 

 were of star-fish ; one showed how new rays are grown by a 

 mutilated individual, and another showed how the starfish opens 

 oysters. The starfish is able to exert a steady pull for five hours 

 if necessary, and the oyster is unable to withstand it, although it 

 can resist a sudden force of twelve pounds. Pictures of echino- 

 derms and holothurians followed, and then a series of lobsters 

 and crayfish and their larvae. The lecturer stated that if a 

 lobster is stroked gently along the back twenty or thirty times 

 it becomes inert, but he was not able to explain the phenomenon. 

 The last slides were of squids and octopuses. Several of them 

 showed how quickly these creatures are able to change their 

 €olour to agree with the background. A vote of thanks to 

 Mr. Martin Duncan was passed by acclamation. 



