PROTOZOA OR SIMPLKST ANIMAI-S, 



.Joblot, who, in IT'it. tirst discovered it pirouetLing ubuiu in an Fli^rh Wall 



infusion of celery, speuk of it iis " ihr most extraordinary fish on 



could imagine." A continual streaming of the protoiilasin rendered Gailcry. 



visible by the granules in its substance is coutinually proceeding up 



and down the pseudopods. The little organism reprorhiccs itst-lf by 



dividing into two (Model 1). 



Actinosp/uerinm ekhoniii (see I*late V. in ihe Case) luis a spherical 

 body with a well-defined outer zone of large vacuoles ; this fornj, 

 which is also abundant in ponds, somewhat resembles a giant Sun 

 Animalcule, being al)out five times the size of Ai:tiii(ij)/iri/s. 



Ii/uij)/ii/iop/ir//s ('/('//an.s may be either solitary (Model .">), nr may 

 form colonies in which several of the spheres are joined l)y bands 

 (Model (J) ; numerous slender curved spicules of silex abound in 

 the surface layer of the body and pseudopods. 



Clathridina eiegans (Fig. 3), which lives in ponds and ditches, 

 may be compared to a Common Sun Animalcule enclosed in a 

 latticed sphere of silex supported on a slender stalk ; the diameter 

 of the shell is about ^^^ inch, and the length of the stalk about 

 Y^ inch. See Model 7 in the Case. 



FORAMINIFERA OR PvETICULARIA. 



The majority of the Foraminifera form a shell of carbonate of 

 lime ; in some, the shell is composed of cemented sand, mud, or 

 sponge spicules, and, in a few species, of inembraiic or silex. The 

 series of Foraminifera mounted on slides is arranged in ten families 

 according to Mr. H. B. Brady's classification, an enlarged figure 

 being placed below each slide. The classified series is ].receded by 

 an introductory account of the group. The small plaster models on 

 steps and on the floor-shelf represent selected types, both living 

 and fossil. 



When the skeletons of Foraminifera were first discovered, they 

 were supposed to be the shells of tiny Cephalopods <.r other :Mo11uscs. 

 Great was the sensation in the scientific world when, in lf<;',."., 

 Dujardin found, from observation of the living animals, that the 

 builders of these complicated shells consisted simply of apparently 

 structtn-eless protoplasm, which extnuled root-like trunks of branch- 

 ing and anastomosing tlireads whereby the creatures crept along 

 (Figs. I, ")). Accordingly he removed these organisms from the 

 MoHusca and placed them in a new grou].. RhixA.j.oda "•/"-■'. ''-■' : 



poui<, foot). 



Foraminiferal shells either have only one or a few main aiKjrtuivs 



