REGENERATION IN A TROPICAL EARTHWORM. 363 



it has been bred from all sorts of decaying matter. The Director 

 of the Imperial Bureau of Entomology writes : " I should be in- 

 clined to suppose that the attack on the earthworms that you have 

 noticed was accidental, for it seems unlikely that this fly would 

 prove to be a true parasite." 



SUMMARY. 



1. P. excavatus, an earthworm occurring in large numbers in 

 dung heaps and soil rich in decomposing organic matter in Ran- 

 goon has a regenerative capacity very much higher than any known 

 at present from megadrilous Oligochseta with the single exception 

 of the limnic Criodrilus lacuwn Hoffm., from Europe. The rate 

 at which regeneration is completed is rapid. 



2. Posterior portions can replace the anterior segments lost if 

 the number of metameres removed is seventeen or less. When 

 more than seventeen segments are removed only ten to fifteen 

 metameres were regenerated. 



3. The posterior limit of head regeneration lies somewhere in 

 the last third of the length of the worm. 



4. Spermathecal apertures and female reproductive pores may 

 develop on regenerating anterior ends. 



5. Anterior pieces of twenty segments or more may regenerate 

 tails. 



6. A heteromorphic head may be regenerated at the posterior 

 end of a very short anterior piece. 



/. A heteromorphic tail may be regenerated at the anterior end 

 of a very short tail piece. 



8. A piece of twenty or more segments from the middle of the 

 worm may regenerate at one end a tail and at the other end a head. 



9. Regenerated heads may be normal, hypomeric, or hypermeric. 

 Hypomeric and hypermeric regeneration is considered an adequate 

 explanation of the origin of abnormalities described as anterior or 

 posterior dislocation of the reproductive organs. 



10. In collections made in various quarters of the town a high 

 percentage of the individuals secured had been mutilated by the 

 amputation of a head, a tail, or both. Many of the mutilated 

 specimens were regenerating the lost parts when collected. 



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