BY VERA A. IRWIX-SMITH. 761 



bucket being covered b\^ miller's silk, to prevent the escape of 

 anvthing but the finest sediment. Fresh water was continually 

 added, till that in the bucket became fairly clear. It was then 

 poured off into another vessel through a coarse wire-sieve to get 

 rid of the more bulky material (some of which was kept for later 

 examination), and concentrated by siphoning or filtering off' most 

 of the water through miller's silk. 



The constant choking up of the silk by the fine sediment 

 caused a good deal of difficulty in the use of the siphon. The 

 same difficulty was experienced in filtering, when the finer 

 quality of miller's silk was used, but I was uncertain whether 

 the coarser quality would catch the CJuetosoraa. It was neces- 

 sary, therefore, to keep the filtrate from the coarser silk, filter it 

 through the finer, and examine the material caught on this, and 

 the water which passed through it. I was also uncertain whether 

 the washincrs sfiven to the bulky material collected were effectual 



DO ^ 



in detaching the worms adhering to the seaweed, etc. 



Until these points were settled, it was necessary to make four 

 separate examinations under the dissecting microscope of each 

 lot of material. 



(1). Seaweed, shales, sponges, etc, 



{'!). Material caught on coarser silk. 



(3). Material caught on finer silk. 



(4). Filtrate from the finer silk. 



I have never found anything but finely suspended mud in 

 No. 4, and, so far, no Chcetosoma in No. 3; so that I think the 

 coarser silk, which filters much more rapidly, can be used with 

 safety. When dealing with small quantities of material gathered 

 along tlie shore, I shake and wash it thoroughly in a jar, and 

 filter off the water directly through the coarser silk, without 

 making use of the siphon. The material caught on the cloth is 

 either washed into a small dish of sea-water for immediate micro- 

 scopical examinaticm, or fixed for later examination. 



Whether the washing is effective or not, seems to depend on 

 the species of worm present. N otocJuetosoma tenax clings so 

 firmly to any support, that it is most difficult to detach it. I 

 had found seseral worms of this species in material which had 



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