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On a Supposed New Infusorian of the Flaoellata 



ElJSTOMATA. 



By George J. Burch. 

 {Read April 24th, 1885.) 



Plate XI. 



In March, 1884, I found in a ditch, by Port Meadow, Oxford, 

 an animalcule, -which I have been unable to identify with any 

 described in Saville Kent's book. It was growing on duckweed, 

 and also on the cases of gnat larvas, of which there were many at- 

 tached to the weed. 



Each colony consisted of a compound stem, no portion of which 

 was contractile, bearing from 10 to 50 heads upon branchlets 

 somewhat thinner than the main stem. These heads appeared, in 

 most positions, of an irregular pear shape, the broad end projecting 

 on one side into a blunt proboscis, from which arose a single stout 

 flagellum. About the centre of the creature was a very strongly 

 refracting oval spot, with a somewhat corrugated surface, which I 

 imagined to be the gizzard. Between this and the mouth, which 

 lies in a cup-shaped depression close under the proboscis, was a 

 passage, the walls of which I could distinctly see, even when there 

 was no food in it. 



The creature was remarkably active, the movement of the flagella 

 being so vigorous as to keep the whole group in constant agitation. 



The flagellum of each individual waved with a steady circular 

 vibration, most often with one node, but sometimes with two, until 

 some particle of food, generally a micrococcus, came within reach. 



Then, before the flagellum touched it, a sudden vigorous stroke 

 was made, which appeared to bring the curve of the flagellum be- 

 hind it, and so throw the food into the mouth. At the same 

 moment, with a rapidity very difficult to follow, the head made a 

 dart forward exactly as a dog snaps at a fly (this movement may 

 result simply from the increased activity of the flagellum, though I 

 incline to believe that the creature has the power of bending the 

 head in various directions on the stem, like Vorticella). Imme- 



Journ. Q. M. C, Series II., No. 13. o 



