38 



ZOOLOGY. 



phus Ehrenberg) we have a rather more complicated form,, 

 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. 27. E/iigtylis Jlamcans Ehr.. a single, many-forked colony of hell animalcules, 

 slightly magnified. Fig. 28, one of the animalcules magnified "250 diameters. ;;, the- 

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

 , the depth of the digestive cavity ; m. Hie mouth ; y, y 1 , the throat, or rudimentary 

 digestive canal ; cv, the contractile vesicle ; //, 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 polymorpUus Ehrenberg, by Hon. 

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

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

 malcules parted, " and the two Stentors swam separately 



