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anterior margin between the two appendages often gives them the appear- 

 ance of tentacles. 



A most striking feature of this worm is its incessant activity. It 

 moves about constantly and makes very active movements when touched. 

 I have never seen a triclad so active. It is quite tough and will recover 

 after being subjected to considerable pressure under a cover slip, crawl- 

 ing about much as before, when returned to the water. The fact that 

 the specimens were obtained from a lot of Mytilus edulis collected at 

 Sandwich Mass. and brought home along with the Mytilus wrapped in 

 a newspaper during several hours travel on a railway, shows further 

 their resistance to conditions fatal to some forms. When the Mytilus 

 were placed in water the worms crawled out of the mass and were dis- 

 covered along the edge of the dish. The water used was that delivered 

 through the supply pipes of the laboratory, and as this often kills deli- 



Sketches of the living worm. G, gut lobes ; Ph, pharynx ; P, penis ; 0, ovary ; T, testes ; 

 U, Uterus; F, Vas deferens. 



cate forms, the fact that these worms survived in the dish for several 

 weeks shows again a considerable power of resistance. These facts 

 suggest the habit of living near the tide line where they may be left ex- 

 posed between tides as is the case with Mytilus. The animals seem 

 accustomed to being out of the water for when placed upon a slide they 

 will leave the drop and strike out across the dry surface leaving the 

 water entirely and finally becoming stranded high and dry. This is si- 

 milar to the behavior of Syncoelidium pellucidum and Bdelloura candida 

 which often crawl up the sides of the dish containing them the addition 



