PROTOZOA OF HERTFOllDSniRE. 117 



the ectoplasm. In its simplest form this exuded structure has 

 a purely gelatiuous consistence, sometimes it is a simple mucus. 



The trausitiou of the structures from a simple gelatinous sheath 

 to a hardened test is well shown in the members of the genus 

 Salpiugwea. 



The composition of the loriea is of a very uniform character iu 

 all classes, having an apparently chitinous consistence. In the 

 majority of instances it is perfectly transparent, but in some 

 genera it assumes with age a deep chestnut hue, and becomes more 

 or less opaque. There is the greatest diversity of form in these 

 protective cases. In the class Flagellata many of the loricoe closely 

 resemble the amphoroo and classic vases of ancient Greece in their 

 exquisite contour and outline. 



Another remarkable form which these excreted structures take 

 is the wonderful tree-like growth of the supporting stalk, or 

 zoodendria, common amongst the Flagellata and Ciliata. A com- 

 plex type is shown in Anthophysa vegetans, where the pedicle is 

 built up of the residual particles of substances first incepted for 

 nutrient purposes, which are excreted from the posterior region 

 and then cemented together by some cohesive mucus. 



One of the most important features to be noticed is the manner 

 in which food is incepted or taken into the body, because the 

 present system of classification is based upon these features. 

 Perhaps it would be as well to here introduce the outline of this 

 system ; but before doing so I should like to say a few words 

 about the term Infusoria, which is occasionally used in this paper. 



Originally it was used to denote almost all minute aquatic 

 organisms, whether animal or vegetable. In its modern applica- 

 tion it includes all those animals belonging to the sub-kingdom 

 Protozoa, which in the adult stage are furnished with the loco- 

 motive or prehensile appendages previously described, and those 

 possessing simple i^seudopodia only are separated into a distinct 

 class called Ehizopoda. The presence or absence of these organs, 

 however, is very variable, sometimes appearing or disappearing at 

 certain stages of development, as in Adinophri/s,^ and sometimes 

 entirely dependent upon the will of the animal. The close rela- 

 tionship which exists is clearly shown upon comparing such types 

 as Dlnamceba with Mastigamceha, Amceba with Reptomonas, or 

 Actiyiophrys with Avtinomonas ; again, the closest affinity exists 

 between the typical Polycystinse and such types as Euchitonia and 

 iSpongocyclia. A close examination will show that all are parts of 

 one harmonious whole, that no lines of demarcation really exist, 

 and that any attempt to separate them must necessarily be arbi- 

 trary ; and it should be borne in mind that these divisions are of 

 value only so far as they assist in classification. The separation of 

 the Infusoria from the Khizopoda appears to me to especially lack a 

 status of any intrinsic value, and were it not for its long association 

 with the study, it would seem advisable to drop the term Infusoria 

 altogether. 



* See Saville Kent's ' Manual of the Infusoria,' p. 225. 



