234 Miscellaneous. 



(Kolpoda, Dileptus). Owing to the latter circumstance, it has often 

 happened that the young and the adult forms of the same animal- 

 cule have been described as distinct species. It is certain, for in- 

 stance, that the Glaucoma scintillans (Ehr.) is but the foetal or im- 

 perfect condition of the Kolpoda cucullus (Miiller). 



In the ova of Vorticellce, having a diameter of '04 of a millimetre, 

 the vitellus clearly manifests gyratory movements, in all respects re- 

 sembling those in the ova of mollusca and other animals. When the 

 young Vorticella is fully developed and on the point of leaving the 

 eggj this gyration is succeeded by movements of another description, 

 viz. by contractions of the entire animalcule, which, as is observed, 

 for example, in^he young Lymnecc, seems to struggle under the 

 transparent envelope of the Q^^. 



In the ova of Vorticellce, the animalcules of which are on the eve 

 of exclusion, I have, in several instances, recognized the existence 

 of the contractile vesicle, and have noted its movements. This vesi- 

 cle was proportionately of less size than in the adult animal, and its 

 pulsations were less frequent. These ova, at this period entirely 

 occupied by the embryo animalcule, presented a diameter of '04 milli- 

 metre, and the contractile vesicle which w^as situated at about the 

 centre, when of its greatest dimensions, '005 of a millimetre. 



In the Vorticell<£ there exists a sac, sometimes very evident, on 

 the side opposite the cardiac or contractile vesicle, and extending 

 nearly the whole length of the animal. The interior of this sac pre- 

 sents very distinct molecular movements, which seem clearly owing 

 to the existence of vibratile cilia. At intervals this sac contracts 

 from before backwards, and seems to transport in that direction a 

 mass, distinct from the stomach vesicles which it compresses. This 

 sac is the respiratory organ ; and its movements have induced some 

 observers to hazard the opinion of the formation of vacuoli in the 

 substance of the animal, or to admit the existence of a form of 

 circulation of granules, such as is noticed in vegetable cells. 



From what proceeds, we must regard the contractile vesicle as a 

 cardiac apparatus*. It is seen to manifest itself like the punctum 

 saliens of oviparous embryos. And hence we cannot with Ehrenberg 

 consider it as belonging to the genital, or, with Spallanzani, to the 

 respiratory apparatus. — Comptes Rendus, Jan. 15th, 1849. 



[If these researches of M. Pouchet be confirmed, an important step 

 in advance has been made in our knowledge of the Infusoria. We 

 can no longer doubt, with M. Dujardin, the existence of ova, and of 

 oviparous reproduction in the true Infusoria or Polygastrica. But 

 until this confirmation be given, such exceedingly delicate observa- 

 tions as those detailed must be received with some reserve ; seeing 

 that imagination, and the desire to indicate an analogy with the 

 higher animals, are too apt to interfere with precise investigation in 

 such minute beings. 



Again, respecting the contractile vesicle said to be observable in 



* Wiegmanii (Archives, 1831) surmised the cardiac nature of this con- 

 tractile vesicle; and Siebold entertains the same idea. — J.'I'.A. 



