ROTIFERA. 55 



One of the essential conditions of the revival of the Rotifers ap- 

 peared to Spallanzani to be their burial in sand : the access of air 

 seems prejudicial to their retention of vitality. MUUer *, the famous 

 Danish observer of Infusoria, only succeeded in reviving them when 

 they were surrounded by foreign particles, and defended from the air. 

 Both Oken and Rudolphi f deny the revival of desiccated animals ; 

 but later observers have succeeded in reproducing the wonderful phe- 

 nomena described by Spallanzani, especially Professor Schultze ; and 

 I myself witnessed at Freiburg, in 1838, the revival of the arachnidal 

 Arctiscon which had been preserved in dry sand by the Professor 

 upwards of four years. 



Summary of the Classes, Orders, and Families of the " Infusoria " 

 of Cuvier and Ehrenberg. 



Class POLYGASTRIA. 



Form, more or less that of a cell. Shell, when present, siliceous or 

 calcareous. 



Motion, a few pedunculate, most are free and move by more or less 

 generally diffused superficial vibratile cilia. 



Digestion, by cavities in a soft parenchyme, without proper walls ; 

 the food taken either by superficial absorption or breach into the 

 parenchyme, or by a mouth into a ciliated dilatable cavity. 



Circulation, by one or more pulsating sacs. 



Respiration, by rotating chlorophyl and by ciliated integument 



Generation, by spermatic nucleus governing partial or total fis- 

 sion of body, by gemmation, and by germ-cells, excluded as such (?), 

 or developed within the body. No distinction of sex. 



Order ASTOMA. Shell, when present, siliceous. 

 Families Monadina. Genera Monas, Microglena, Chilomonas, 



Bodo, Gregarina. 

 AsTAsiiNA. Amhlyophys, Euglena, Chlorogo- 



nium. 

 Peridinina. Peridinium, Glenodinium. 



Opalinina. Opalina. 



AcTiNOPHBYNA. Actinophrys. 



Order STOMATODA. Shell, when present, siliceous. 

 Families Vorticellina. Genera Stentor, Trichodina, Vorticella, 



JEpistylis, Carchesium. 

 Ophrydina. Vaginicola, Cathurnia. 



Enchelia. Leucophrys, Prorodon. 



* XLIV. p. 98. t XLV. Bd. I. p. 285. 



£ 4 



