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BELL ANIMALCULE. 



STRUCTURE 



FIG. 1. Bell-shaped body with slender stalk for attachment. 



/ Cuticle, a very thin layer of protoplasm investing the body. 

 Disc, covering the mouth of bell and fringed with cilia. 

 Peristome (Gr. peri, around ; stoma, a mouth), the ciliated rim separated from the edge 



of the disc by a groove. 



Vestibulum (L. an entrance), a depression in the groove where food enters by a 

 permanent mouth. The undigested matter passes out by a temporary anus (L. a 



, \ 



vent). 



(Eso'phngus or gullet, leading from vestibule into the soft body-substance. 

 Food-vacuoles, food-particles enveloped iu water and dropped off from the end of the 



gullet. 



Contractile vesicle. 

 \ Curved nucleus. 

 f Sheath, a continuation of the cuticle. 



1 Axis, the central muscular fibre. 



DIAGRAM OF THE PAEAMCECIUM OK SLIPPER ANIMALCULE, A FREE SWIUHING INFUSORIAN 

 Cuticle and cilia. 



Cortical layer with two contractile vesicles. 

 Body-substance like soft-boiled sago. 



Funnel-shaped mouth opening by a short gullet into body-substance. 

 Anus, merely a temporary opening. ' 

 MOVEMENTS 



FIG. 2. The spirally-coiled stalk, the retracted disc, and the curved-in peristome. 

 FIGS. 3, 4. Encysted forms stalked and unstalked. 



Mu LTIPLIC ATION 



FIG. 5. Longitudinal fission ; a bell divides lengthways into two, and the detached portion finally 



becomes like the original. 

 REPRODUCTION 



FIG. G. A free-swimming bell fuses with a stalked form, producing a single individual; this is the 

 so-called process of conjugation. The attached bell was formerly taken for a bud. (Pos- 

 terior cilia not shown.) 

 CLASSIFICATION 



Sub- Kingdom Protozoa. 



Natural Order Infusoria, because it possesses an outer layer (ectosarc) provided with cilia and 

 contractile vesicle or vesicles, and an inner substance (endosarc) with nucleus, and usually 

 with a mouth leading into it and an anus leading out. They occur in infusions, hence 

 the name. 



Genus Vorticella, so named from the vortex caused by the moving cilia. 

 Common Name Bell Animalcule. 



