The Monad's Place in Nature. 217 



to tlie glass after the turpentine has been j^laced over them. In 

 such a case, the process, as above detailed, must be carried out on 

 the original slide, and then, after the benzole is thoroughly evapo- 

 rated, water must be applied two or three times in the same way as 

 the benzole for the purpose of washing away the gum and freeing 

 the diatoms, which can then, when dried, be lifted one by one and 

 transferred in the usual manner. 



By this simple and easy method we can not only select from 

 balsam-mounted gatherings any particular valves we may require, 

 but we can reset any spoilt or unsatisfactory mounts of our own. 



VI. — Tlie Monad's Place in Nature. 

 By Metcalfe Johnson, M.K.C.S.E., Lancaster. 



Plate CIII. 



Among the objects in the department of Protozoa one sees at the 

 same time groups of organisms having attained a certain degree of 

 perfection, and other living forms in a more elementary condition. 

 The object of the present remarks is to show a connection between 

 the earlier forms, which we call Monads, and those higher and more 

 comj)licated organisms at j)resent recognized under the name of 

 Infusoria, Mucedinae, Confervse, Oscillatoria, &c. 



The following record of experience, taken together with the 

 previous papers in ' Monthly Microscopical Journal,' will be found 

 to contain some evidence bearing on the tendency of certain or- 



DESCRIPTION OF PLATE CIII. 



Fig. I. — A tubule of Vauclieria, containing : — a, mass of cbloroi^liyll ; h, bursting 

 of tubule and discliarge of Monads, &c. ; c, a green oval Gonidiuni ; 

 d, two Monads moving witbin tbe tubule ; e, an immature Pseudo- 

 gouidium ; /, an Euglena ; g, a mass of cbloropbyll giving oft', /(, a 

 globular extension of the primordial utricle ; i, the terminal vacuole 

 of tbe tubule containing Monads in active motion ; k k, two Pseudo- 

 gonidia being discharged from the tubule ; I, a transparent primor- 

 dial utricle, or empty eel 1- wall ; h(, the same, containing- chloroijhyll ; 

 n, one of these in the act of bm-sting, and liberating, p, the Monads, 

 which at once take an independent cyclical movement. 



„ 11. — A piece of Conferva rkularis : «, the hole through which tbe Euglenas, 

 6, are escaping. This observation was made April 11th, 1809. 



„ III. — A pin-point Monad in its transformation to Confervoidsea. 



„ IV. — A pin-point Monad in its transformation to Penicillium. 



„ V. — A pin-point Monad in its transformation to Chlorococcus : c, Gonidium ; 

 h, Gleocapsa ; c, commencement of Soridium ; d, e, biflssation ; /, division 

 into 4 ; </, division into IG ; /*, formation of JThalUis or Apothecium. 



„ VI.— A pin-point Monad in its transformation to Euglena : a, Gonidium ; 

 b, oval cell with vacuole ; c, Euglena ; d, with filament ; e, intersus- 

 cepted form. [Fig. vii. 



