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ficient knowledge of those genera, which de Beauchamp maintains are placed very 

 incorrectly and used by me as intermediate stages between forms which ac- 

 cording to his idea have nothing to do with each other, I do not wish here to 

 enter too much into details. 1 hope later on to be able to show that on some of 

 the points where our views do not coincide, my arrangement is not so "fantastic" as 

 DE Beauchamp seems to think. 



Here I onlj' take the liberty to give a short summary of the results at which 

 I arrived in 1899, and which I am unable to alter upon essential points. It is upon 

 these results that my systematic views, which I shall finally set forth in a few 

 words, are based. 



The cuticula of the Botifera is originally segmented; the lorica, which arises 

 owing to coalescence of the middle segments, and in which the anterior and posterior 

 segments may be drawn in, is a derivation of the hyaline segmented cuticula. 



The original wheel-organ of the Botifera is a ventrally placed ciliacovered 

 disc, without any specially developed wreath of cilia, bordering the disc; the mouth 

 lies excentrically in the hindpart of the disc. Animals, equipped with wheel-organs of 

 this type, are slowly creeping; the swimming power is extremely small, and the 

 motion, in swimming, is along a straight line, not rotating. The wheel-organ is un- 

 able to procure food during the swimming motion. 



The more a type of the Botifera is emancipated from the substratum, passing 

 over from a creeping to a swimming organism, the more terminally is the cilia- 

 covered disc placed, and the more will the cilia, bordering the disc, be equipped as 

 a ciliary wreath; simultaneously with this, the cilia coating of the disc will diminish, 

 and finally the disc will be almost or totally nude. The locomotion passes over 

 from straight to screwformed; the number of rotations is dependent on how 

 much the ciliary wreath is developed in relation to the cilia of the disc. In the 

 most aberrant types of the wheel-organ, it is further modified in such a way, that 

 it is able to capture food during the swimming motion. In accordance with this 

 the disc is often first cleft in two half, between which the mouth is placed; then a 

 new wreath of cilia will be developed, either inside or outside the primary ciliary 

 wreath; the main purpose of this second wreath is to prevent the organisms, caught 

 by the primary wreath, from escaping and to carry them safely to the mouth opening. 

 In accordance with this, a furrow, bordered by the two ciliary wreaths, the loco- 

 raotory wreath and the stopping wreath, is developed; through this furrow the nour- 

 ishment is carried to the mouth by means of cilia. 



I arrived at this main result with regard to the wheel-organ, more from the 

 study of the manner in which the animals used the organ, than from an anatomical 

 investigation. With low powers, equipped with a small microscope, often in nature 

 itself, I studied the animals in open vessels; later on I only used a very strong 

 lens, observing the animals in high cylindrical vessels. From his anatomical studies, 

 as far as I can see without a more thorough study of the freeswimming organisms, 

 DE Beauchamp (in 1907 and later on in 1909) arrived at a result, which in its 



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