S48. Dr Wagner ow the Structure and 



4. The nearly ripe eggs are the most transparent, particularly 

 on their margin. The embryo is often perfectly formed, quite 

 transparent, and the cilias are in active motion in the interior of 

 the egg, I The head of the animal, on the rotatory organ, is 

 generally turned towards one or other of the ends of the oval 

 eggs. Frequently the embryo turns quite round in the tgg^ by 

 means of a sudden motion bringing its rotatory organ to the 

 opposite extremity. I gently pressed several of the ova between 

 plates of mica, and was fortunate enough to split the envelope, 

 so that the embryo started out ; it was commonly very much 

 contracted, the tail drawn in, so that I imagine the embryo does 

 not lie curved on itself, but contracted ; but I may be deceived 

 in this as in other cases. I thought that I observed a turned 

 posture. The teeth and the mouth seemed to be the first 

 formed ; for, on one occasion, I pressed out of the egg a fetus 

 which had not yet begun to vibrate its cilias, but in whom these 

 organs, as well as the bifurcated tail, were quite distinct. In 

 those who had begun to move their rotatory organ in the egg^ 

 I recognised, in addition, the perfectly formed colourless intes- 

 tine and the ovary. Twice I saw the exclusion of the embryo. 

 The shell split transversely, and the animal immediately pro- 

 truded its rotatory organ, and in about a minute slowly extri- 

 cated itself from the egg^ extended itself at full length, and be- 

 gan to swim slowly forwards. All its parts were perfectly 

 formed ; it was quite transparent, and was only at first a little 

 curved. But the intestine was constantly quite colourless. The 

 largest was about ^"' long. The remnant of the envelope of 

 the egg was transparent and fissured in different directions. 



The development of the ova in the ovarium was another sub- 

 ject of my observations. Even in animals just excluded from 

 the egg, I could observe the individual ova in their interior. By 

 slight pressure of the animalcule between plates of mica, the ova- 

 rium, as well as the intestine, was rendered very distinct, and 

 by attentive inspection, there could be detected seven very small 

 oval ovules, which had a black spot in their middle, which I 

 reckon their yolk. Similar ovules were perceptible in an ani- 

 malcule about Y' loJ^gj which having already eat, had its in- 

 testine of a greenish colour. In a grown animalcule of J"', in 

 which the intestine was quite filled with dead Euglena, I saw 



