But within a short while we were fortunate 

 enough to collect at least a dozen more of those 

 much desired haunters of the dim and dark pre- 

 cincts of the pool. Here occurred a curious thing. 

 No sooner was another flatworm placed in the vial 

 with the first-found form than the latter began to 

 show a marked activity. It released its hold from 

 the glass and swam to the other, and after circling 

 around the new-comer several times, came to rest 

 at its side so close that their bodies touched. 



Now this may mean much or it may mean noth- 

 ing. Still, in view of subsequent observations with 

 these creatures in the laboratory, a partial meaning 

 can be found in their manifestation of sexual at- 

 traction; this behavior is in line with what not 

 infrequently takes place preliminary to mating. 

 However, what is more immediately to the point, 

 it seems to suggest something also which is beyond 

 physical considerations. 



The flatworm, as I have already indicated, is a 

 hermaphrodite. It is a noteworthy fact that most 

 many-celled sedentary organisms have both male 

 and female powers of reproduction. Plants in par- 

 ticular are well-known examples having this dual 

 power; but its possession by animals, though not so 



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