Development of Rotifer vulgaris. 143 



birth of these animals. I confess ray complete ignorance 

 upon this point. 



V. The Reproduction. 



On the 15th February, 1884, I found in one of ray glasses 

 some examples of Rotifer which showed eggs of the known 

 size and form floating in the body-cavity, but besides these 

 bore, attached to the inner surface of the cuticle, other egg- 

 like structures, which seemed to derive their origin (by gem- 

 mation) from Leydig's " granular layer." 



This was to me an extremely unexpected and startling 

 sight. On closer examination the whole of the Rotifers in 

 the glass in question proved to be furnished with such ova of 

 the second kind. By selecting suitable examples it was 

 possible to follow the progress of the process of budding with 

 the greatest distinctness. Every drop of water that I placed 

 upon an object-slide contained ten or twelve Rotifers. In 

 these the budding-ova could be observed in all possible stages 

 of maturation. 



But were they really " ova " that here presented themselves 

 to observation ? This question naturally occurred to me, and 

 I examined the literature that I had at my disposal in con- 

 nexion with this point. But nowhere could I find any state- 

 ment from which I could infer that before me any one had 

 observed such budding-ova in Rotifer. Unexpectedly there 

 came into my hands a note in the ' Archiv fur Naturge- 

 schichte ' (1871, Bd. ii. p. 468), according to which Ganin 

 had ascertained the formation of eggs by budding in Galli- 

 dina parasitica (a Philodinid parasitic in Qammarus pulex). 

 According to Ganin's report the egg-buds originate from the 

 matrix ot the cuticle, surround themselves immediately with 

 a structureless membrane, become further developed, and then 

 separate by constriction. But, together with these, true ova 

 capable of development are also produced by the same wheel- 

 animalcule. 



This note agreed admirably with my own observations. I 

 had seen the development of the buds from the granular layer 

 ( = matrix). I had accurately ascertained that these gradually 

 grow into ellipsoidal structures, which, in external form, 

 exactly agree with the ovarian ova of Rotifer vulgaris. 

 However, the matrix-ova observed by me remained in con- 

 nexion with their place of origin even after they had attained 

 their definitive size. It was only in a few instances that I 

 found them floating in the body-cavity like the ovarian eggs. 

 Otherwise they always had their anterior extremity imbedded 

 in the granular layer, and a small process even passed into 



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