M. Balbiani on the Generative Organs of the Infusoria. 439 



EXPLANATION OF PLATE XL 



Fig. 1. Bairdia Jonesiana, n. sp. : right valve; magnified 30 times. 



Fig. 2. Bairdia Jonesiana, a less elongate form : right valve ; magnified 

 30 times. 



Fig. 2 a. Bairdia Jonesiana : lateral contour. 



Fig. 3. Bairdia rhomboidea, n. sp. : right valve ; magnified 26 times. 



Fig. 3 a. Bairdia rhomboidea, lateral contour. 



Fig. 4. Bairdia truncata, n. sp. : cast of right valve ; magnified 38 times. 



Fig. 4 a. Bairdia truncata, lateral contour. 



Fig. 5. Leperditia ? Permiana, Jones : right valve, having a smooth sur- 

 face ; magnified 26 times. 



Figs. 6 & 8. Leperditia ? Permiana : right and left valves, showing a 

 wrinkled surface ; magnified 26 times. 



Fig. 7- Leperditia 1 Permiana: left valve of a specimen with a punctured 

 surface ; magnified 30 times. 



Fig. 9. Leperditia ? Permiana : left valve of a young specimen ; magnified 

 38 times. 



Fig. 10. Leperditia"? Permiana: ventral aspect of a specimen showing 

 lateral compression and marginal rims ; magnified 26 times. 



Fig. 11. Leperditia"? Permiana: ventral aspect of a more globose speci- 

 men, showing marginal rims, punctured ; magnified 30 times. 



Fig. 12. Leperditia"? Permiana: dorsal aspect of the last specimen; mag- 

 nified 30 times. 



Fig. 13. Leperditia"? Permiana: interior of right valve; magnified 30 

 times. 



XLVII. — Investigation of the Generative Organs and Reproduction 

 of the Infusoria. By M. Balbiani*. 



In a preceding communication f I had the honour of communi- 

 cating to the Academy some of the results at which I had arrived 

 in studying the reproduction and development of the Infusoria 

 called Polygastrica in the classification of Ehrenberg. In the 

 course of the present spring and summer I have been able to 

 extend my researches to several other species, and to complete 

 some old observations which the want of materials had compelled 

 me to interrupt for a time. The object of the present note is 

 to make known the most essential of these new results, the de- 

 tailed exposition of which will form the subject of a memoir 

 which I propose shortly to submit to the Academy. 



The investigation of the propagation of Paramecium Bursaria 

 had led me to assume in this species, independently of a multi- 

 plication by spontaneous scission, a second mode which consti- 

 tuted a true sexual generation, and to recognize in the organs 

 described under the names of nucleus and nucleolus the analogues 

 of the male and female generative organs of the higher animals. 



* Translated from the 'Comptes Rendus,' 30 August, 1858, p. 383, bv 

 W. S. Dallas. 



t See < Annals,' 3rd series, No. 6. p. 435. 



30* 



