118 F. W. PHILLIPS NOTES ON THE 



There are four great sections of the Protozoa. The first is called 

 Pantostomata, and includes all those animalcules which have no 

 true mouth, or inceptive area, but are able to incept food in- 

 differently at any part of the body, after the manner of the typical 



In the second section, Discostomata, the inceptive area is limited 

 to a discoidal or circular region, but it does not constitute a true 

 mouth or aperture. 



In the third section, Eustomata, we find a single but distinct 

 mouth or oral aperture, as in Stentor and Vorticella. 



The fourth section is called Polystomata, and here we find a 

 great number of such apertures or mouths ; an example of this is 

 afi'orded by Acineta and its allies. 



These four sections are subdivided into classes, according to the 

 nature of the appendages they possess. The first section, Pantosto- 

 mata, with which we have now to deal, is divided into two classes, 

 Ehizopoda and Plagellata. 



The Ehizopoda are those animalcules whose appendages are 

 pseudopodic, lobate, or radiate. This class, of which the well- 

 known Amoeba is a representative, is further divided into six 

 orders, which I shall enumerate further on. The Flagellata are 

 distinguished by the possession of one or more whip-like append- 

 ages called flagella ; they are divided into five orders. 



In these remarks which I have made concerning the classification 

 I have digressed somewhat, but it has been with the view of cur- 

 tailing the remarks relating to the physiology of the Protozoa, 

 because, as far as it is possible, I wish to speak only of the 

 pantostomatous section. We have considered the ectoplasm or 

 cuticle of an Infusorian, and now, for a short time, I wish to 

 draw your attention to the endoplasm, or contained matter. The 

 most prominent feature we notice is a clear, spheroidal space, ex- 

 panding and contracting Avith a regular rhythmical motion, wliich 

 is distinguished by the title of contractile vesicle. This organ early 

 attracted the attention of observers. Opinion has been, and is still, 

 much divided as to its exact structure and function. Ehrenberg 

 first described it as a spermatic gland ; Spallanzani and Dujardin 

 considered it a respiratory organ ; Lieberkuhn, Claparede, and Lach- 

 man recognised it as a rudimentary heart or organ of circulation ; 

 while, according to Oscar Schmidt and Stein, its functions are 

 excretory. Prof. Haeckel, however, most reasonably maintains 

 that its functions are twofold, being both respiratory and ex- 

 cretory. A long-disputed but most important point is whether 

 or not a communication is maintained with the outer, inhabited 

 water. 



By nearly all the earliest writers it was maintained that no such 

 communication took place ; a contrary decision, however, was first 

 arrived at by Oscar Schmidt and Mr. H. J. Carter, and strong 

 additional evidence given by Prof. Pay Laukester has called foi-th 

 testimony from various sources establishing this intercommunication 

 beyond a doubt. Mr. Saville Kent argues well that the leading 



