THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[SECOND SERIES.] 

 No. 83. NOVEMBER 1854. 



XXTX. — Contributions to the Natural History of the Infusoria. 

 By A. Schneider*. 



[With a Plate.] 



I. On Polytoma Uvella. 



Polytoma Uvella is given by Ehrcnbergf as the only species of 

 the genus Polytoma, and characterized in the following words : — 

 " Animal e familia Monadinorum, ocello destitutuin, ore termi- 

 nali truncato, ciliis aut proboscide subtili flagelliforme duplici 

 instmcto natantibus solitariis antico, divisione spontanea decus- 

 sata et imperfecta, multipartitum in Mori form am enascens, dein 

 partitum et altera vice solitarium." In a subsequent passage he 

 adds — "With regard to its organization the polygastric ali- 

 mentary organs appeared distinctly. Besides these I perceived a 

 larger contractile vesicle, which did not belong to the nutritive 

 apparatus, and which appeared to be connected with the male 

 sexual organs. Lastly, a large, free, white spot in the anterior 

 part of the body, the outline of which could not be made out 

 distinctly, but which pressed the stomachal sacs towards the 

 hinder extremity, led to the supposition that a seminal gland 

 existed in that place." After repeated failures he succeeded, 

 but only by employing a magnifying power of 6-800 diameters, 

 in seeing the little sacs of the posterior portion filled with indigo. 

 Dujardin, apparently, has never examined Polytoma himself, as 

 he could not repeat Ehrenberg's observations upon its mode of 

 division J, and I am unacquainted with any subsequent obser- 

 vations upon this creature. 



* Translated from Mutter's Archiv, 1854, p. 191. 

 t Die Infusorien als volkommene Organismen. &c, p. 24. 

 % Dujardin, Hist. Nat. Infusoires, p. 276. 

 Ann. 6f Mag. N. Hist. Ser. 2. Vol. xiv. 21 



