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 PROCEEDmGS OF THE SOCIETY. 



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globular, surrounded by an equatorial belt of cilia, having two red eyes, 

 and almost tlie whole of the animal's structure lying in the upper 

 hemisphere. The point he should like to get confirmed was the action 

 of the contractile vesicle, a large kind of bladder opening into the 

 cloaca, but entirely detached from the lateral canals, which came into 

 the cloaca independently. It was generally thought to be an excretory 

 system, and that the excretory products passed out into the contractile 

 vesicle and thence into the cloaca. In some of the animals it was 

 remarkable to note that the contractile vesicle was very large in 

 -proportion to their size, being nearly 1/3 the size of the creature, and 

 when it was seen that it would contract and fill again in about 1/3 of 

 a minute, discharging each time a bulk of fluid nearly equal to 1/3 

 the size of its own body, it became a question whether so much 

 excretory matter could be produced in so short a time, or whether it 

 was, after all, water which was taken in and passed through. For his 

 own part he did not see any reason why both ideas should not be true, 

 and that there should be a mixture of the two fluids. Cohn, in en- 

 deavouring to test the action, put some pigment into the water, 

 and he saw some of the pigment particles afterwards in the contractile 

 vesicle, and though it was possible that he might have been mistaken 

 as to the plane in which he saw these particles, through not using a 

 binocular Microscope, yet he was himself inclined to think the obser- 

 vation was a correct one. That the contractile vesicle did drive 

 water out of the cloaca was positively certain. By means of a 

 drawing on the board it was shown how in the male of Asplanchna 

 the tube swelled out at one part, forming a kind of bulb which was 

 seen to traverse the tube during the action of the contractile vesicle. 

 He thought the Society would be glad to know that TrochospTisera had 

 got as near as Australia, and hoped that it might be found in this 

 country before long. 



Prof. Stewart said he quite agreed with the President that they 

 had in these cases to deal with an indrawing and a driving-out process, 

 and he found a parallel in the case of the Infusoria, having seen a 

 non-living particle lying near the mouth of the contractile vesicle shot 

 out suddenly by the action described. He had come to the opinion that 

 it was mainly filled with the drainage from the watery media by which 

 it was surrounded, and that at the same time it to a certain extent took 

 in water as well. As another case of curious coincidence of the finding 

 of a new species in widely different localities about the same time, he 

 remembered that in 1856 Mr. Carter described a new genus Otostoma in 

 the 'Annals and Magazine of Natural History.' In this— as shown by a 

 drawing upon the board — the bars were arranged in a beautiful shell- 

 like form, spirally curled, from which circumstance it received its name. 

 Within a week of the appearance of the description in the Annals, he 

 found the same creature in the water filling the impression of a cow's 

 foot in the neighbourhood of Plymouth. It might have been overlooked, 

 but as his friend — to whom he was at that time acting as jackal in these 

 matters — had been for some time engaged in making accurate drawings 

 of all species to be found in the locality, he thought that it was not 

 likely to have been the case ; but he remembered very well bringing it 

 in, and that as soon as it was seen his friend exclaimed, " Good gracious ! 

 it s a new thing ; why it is the same as described in the Annals." 



