168 Transactions of the 



changes in solutions of organic matter, are a dangerous form of 

 organism to be taken into the human system. 



Finally, the results of my experiments are in accordance with 

 the theory, now almost universally accepted, of the general difiusion 

 of germs ; and once a suitable soil is produced for any class of 

 these germs they will soon find it out and begin to grow, just as 

 bacterian bodies develop in New Eiver water immediately after a 

 small proportion is added thereto of phosphate of potash and cane- 

 sugar respectively. 



III. — On the Winter Habits of the Rotatoria. 

 By Charles Cubitt, C.E., F.E.M.S. 



{Read hefore the Eoyal Microscopical Society, March 1, 1871.) 

 Plate LXXXI. 



Every step we take in the investigation of the habits and functions 

 of this interesting Class of the animal kingdom leads us to the con- 

 clusion that while a reliable classification is stiU wanting, facts are 

 being daily established on many hitherto doubtful points in their 

 economy which are tending towards the establishment of a rehable 

 basis for such a desirable end. 



I have for some successive winter seasons directed my attention 

 to these particulars as far as the tube-builders are concerned ; and 

 as it appears from the published records of kindred societies that 

 much misapprehension still obtains on certain points in the eco- 

 nomy of this interesting CLASS, I beg leave to preface the consi- 

 deration of the subject proper by a few prelusory remarks on the 

 points in question. 



It wiU consequently be necessary for our purpose to distinguish 

 the members of the Loricated Families of SECTION I. of the 

 CLASS PtOTATOEIA of Ehrenberg's SYSTEM under two Divi- 

 sions, — the Solitary Fixed, which include Melicerta, Limnias, 

 G'lcistes, Tuhicolaria, Stephanoceros, and Floscularia ; and the 

 Clustered Tree, which contain only Lacinularia and Conochilus ; 

 for while these disagree in points of habit they are identical in an 

 important point in their anatomy, which by careful and persistent 

 investigation I have proved and recorded.* They, one and all, 

 whether ciliated or setigerous, possess a secondary range of vibra- 

 tile cUia situated anteriorly to the mouth, the marginal wreath 

 being constituted to act as a foraging organ, in collecting a hetero- 

 geneous mass of particles about the disk ; but the secondary range, 

 acting in conjunction with certain ciliated lobular process, exercise 

 a discriminating function in selecting from the heterogeneous mass, 

 * 'M. M. Journal,' May, 1870. 



