38 



ZOOLOGY. 



phus Ehrenberg) we have a rather more complicated formj 

 the infusorian attaching itself at one end by a stalk, and 

 building up a slight tube, into which it contracts when dis- 

 turbed. The Stentor may be sometimes observed multiply- 

 ing by self-division. Clark observed Stentor polymorphus 

 undergoing the process. The first change observed was the 

 division of the contractile vesicle into two. The mouth of 

 the new Stentor was formed in the middle of the under side, 



Fig. S7. — EpisUjlis fxivicans Ehr., a single, miiny-forlvci co'ony of hell ammalcnles, 

 Blightly magnified. Fig. 28, one of tile animalcules magnified 350 diameters, p, the 

 stem; d, the flat spiral of vibrating cilia at the edge of the disk; ms, the muscle; m to 

 A', the depth of tlie digestive cavity ; m, the mouth ; g, g^^ the throat, or radinieDtary 

 digestive canal ; cv, the contractile Tcsicle ; //. the reproductive organ or nucleus. — 

 After Clark. 



first appearing as a shallow pit, around which arises a semi- 

 circle of vibratile cilia. The mouth and throat form in the 

 new Stentor before any signs of division appear, but in the 

 course of two hours the body splits asunder, and two new in- 

 dividuals appear. Fig. 26 illustrates the mode of self- 

 division seen in Stentor polymorphus Ehretiberg, by Hon. 

 J. D. Cox. The process in this occupied two hours ; at the 

 final stage (Fig. 26, /) the connection between the two ani- 

 malcules parted, " and the two Stentors swam separately 



