Development of' the Infusorial 5^49 



the ovary to contain nine eggs, of different degrees of ripeness 

 as well as size. The smaller had a distinctly granular interior, 

 and a dark point in the centre, the larger were quite opake. 

 The animal evacuated the contents of its intestine by an anus, 

 and also excluded the ova by means of the cloaca and the same 

 opening. During this operation I observed the distinct con- 

 traction of the vesicular organ seated below the organs of gene- 

 ration, and which Ehrenberg views as the muscuLus ejaculator 

 seminis. The small ova escaped most easily, the larger were a 

 somewhat longer time of making their exit, and usually broke 

 during the passage, and evacuated their granular contents. If 

 the uterus was distinctly two-horned, as in Ehrenberg's figure, 

 each horn contained four eggs, the lowest one was the largest 

 (/o'"), most transparent at the edges, and with the dark granu- 

 lar mass still in the interior. The three uppermost eggs were 

 commonly oval, and had also a central darker nucleus. The 

 ovarium thus contained simultaneously ova in very different 

 stages of development. 



Much similarity will be found to exist between these frag- 

 ments of a history of the development of a Hydatina and the 

 tables which Carus has given of the Lacinularia Jluviatilis. 

 Here the Qgg is formed of a chorion and an albuminous mass 

 (yolk), which forms the embryo. The rotatory organ here also 

 moves in the egg, from which Carus concludes this oscillation 

 to be the respiratory act, which thus takes place in the fetus be- 

 fore any nutrition can be conceived to take place by the mouth. 

 I am also disposed to adopt the same view of the rotatory organ 

 being the apparatus for respiration, but its complete establish- 

 ment would require some connection to be traced between the 

 respiratory and the circulatory systems, and a more complete 

 demonstration of the existence of the latter than we as yet pos- 

 sess. Something similar seems to occur in the embryos of the 

 leech, which, according to Weber, move about and swallow al- 

 buminous matter. 



11. Eggs qftlie Voriicella larva, Miill. 



I have already mentioned that there existed cotemporaneouf;ly 

 with the Hydatina senta in the water, a smaller animal, which 

 exactly agreed with the Vortkella larva, as figured in the En- 



