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.—Hpistylis flavicans Ehr., a single, many-forked colony of bell animalcul 
slightly magnified. Fig. 28, one of the animalcules magnified 50 diameters. Bs tha 
stem; d, the flat spiral of vibrating cilia at the edge of the disk; ms, the muscle; m to 
8, the depth of the digestive cavity ; m, the mouth ; g, 1, the throat, or rudimentary 
Seetre cae cv, the contractile vesicle ; , the reproductive organ or nucleus.— 
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 Ehrenberg, by Hon. 
J. D. Cox. The process in this occupied two hours ; at the 
final stage (Fig. 26, f) the connection between the two ani- 
malcules parted, ‘‘and the two Stentors swam separately 
