Notes on the Preceding Paper, 



55 



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Pond Life, and I still maintain it to be substantially correct, 

 although the attitude is more exceptional than I then thought. 

 In that position the gizzard cannot be seen distinctly, as the 

 observer looks down into the open disk as he would into a 

 tea-cup held with its mouth slanting towards him. The feeler 

 appears surrounded by cilia, and situated near one margin of 

 the rim. This state of things is not common, but I have dis- 

 tinctly seen it since ; and it will be understood, on referring to 

 Fig. 1, which also represents an exceptional, but very con- 

 venient disposition of parts. In that sketch the 

 proboscis, or feeler, is shown to be seated upon a 

 prominence, which varies in shape, and is capable 

 of considerable motion. When this is thrust for- 

 ward, the proboscis is carried within the ciliary 

 circle as I first saw it, and as my wife delineated it. 

 The usual attitude of the animal before the disk 

 is opened is like Mr. Gosse's Fig. e, the eye how- 

 ever being seldom visible. When the expansion 

 occurs, the amount of protrusion of the body, and 

 the angle at which it is bent, vary indefinitely. 

 Perhaps the commonest position is for the body 

 to be nearly upright, with the upper part bent 

 at an angle like the handle of a walking-stick. 

 The cilia are very long; they vibrate through 

 their entire length, and often exhibit a row of 

 retreating and a row of salient curves. In my 

 Fig. 1, the body is unusually protruded, the pro- 

 jection above the tube, on the left, being the 

 anus. In this sketch the disk is circular and con- 

 tinuous, except immediately in front of the pro- 

 boscis, where a depression occurs, forming a sort 

 of notch, but not nearly deep enough to justify 

 the epithet "bilobed." I believe the animal can 

 fill up this little notch by bringing the sides to- 

 gether, and relaxing the muscular contraction by 

 which that portion of the margin is pulled down Fig. 2. 

 below the general level. 



The tubes are generally as described by Mr. Gosse, but I 

 have met with a few of unusual length, slightly twisted and 

 strangely bent at the top on one side. In some specimens, 

 probably young, they are transparent enough to allow the 

 animal to be seen all the way to the bottom, and in that state 

 are so flexible as to move about as it moves. What share the 

 faecal pellets may have in colouring the tubes I do not know ; 

 but, with one exception, the darkest food I have seen in healthy 

 individuals has been of a very pale yellow-brown, very much 

 lighter than the nocculent adhesions. 



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