Transmutation of Form in certain Protozoa. 185 



four more globe-forms added, all clustered together. One of our 

 members thought he observed a little ciliary action on one, and when 

 I looked at it again, I saw that it was a Trachelius, and similar to 

 your sketch 63, but minus the ciliary marks. The snout was there, 

 and full of revoMng vesicles. It quietly stretched itself out and 

 swam away, and after short intervals all the others made off. Since 

 then I have had an instance of a Trachelius rubbing itself amongst 

 the branches of a Carchesium, and a few of the heads gone and 

 other heads becoming encysted and assuming a pyriform shape ; but 

 unfortunately my tank gave way, and there was an end of my expe- 

 riences. What I have observed in my trough is strongly confirma- 

 tory of your observations. I have sometimes had nothing but 

 Amoeba; at another time Paramoecium, Kerona M. Vorticella in 

 abundance; at another Philodina, Botifer vulgaris, and sometimes 

 Floscularia, &c." 



It is in the highest degree satisfactory to find that observers of 

 the careful class to which this gentleman belongs not only sympa- 

 thize in the researches to which I have now devoted some little time, 

 but are enabled to confirm my suggestions by kindred observations 

 of their own, assisted by their microscopical friends and associates. 



In the Plate accompanying this paper (Plate C.) will be found 

 the rough delineation of forms which I have observed in various 

 liquids containing vegetal matter, and which I have watched during 

 their transmutations to forms which have eventually proved them- 

 selves to belong to the class Philodinaea. It will be my object to 

 endeavour to show that the members of this class are not forms 

 having specific distinction, such as in tracing their origin we should 

 find derived from separate sources, but simply stages of develop- 

 ment of one common form of animalcular existence. 



I will first, then, proceed to give some explanation of Plate C. 



Figs. 1 to 7 are the varying forms of an Amoeba, which, com- 

 mencing as an Actinoj^hrys Sol, passed through its stages, termi- 

 natmg in a form which closely resembles a Paramoecium. 



Figs. 8, 9, 10, and 11 are varying forms of a species of Para- 

 moecium, possibly Loxodes Bursaria. Fig. 8 represents the Infu- 

 sorium in the natural state, the revolving vesicles being in active 

 motion. Figs. 9, 10, and 11 are under the influence of opium, in 

 which the revolving vesicles are separated from the other part, 

 which is intended to represent globules of sarcode, which in Fig. 1 1 

 so closely resembles an Amoeba as to render it very interesting in 

 relation to Figs. 1 to 7. 



Fig. 12 is a globular condition of a Philodina, showing the 

 vesicles well developed. 



Fig. 13 is a more advanced stage of the same Infusorium or 

 Eotifer. 



