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STUDIES IN ENCHYTRAEID WORMS. 

 HENLEA FRAGILIS FRIEND. 



By the Rev. HILDERIC FRIEND, F.R.M.S. 



(With Plates XXVII— XXXII.) 



The object in view in preparing these Studies is to supply an accurate 

 and detailed account of British White Worms or Enchytraeids. These 

 researches have been carried out in the Department of Agricultural 

 Zoology, Birmingham University, which is under the direction of 

 Prof. Gamble, D.Sc, to whom the writer here acknowledges his 

 indebtedness. 



In the following pages the Genus Henlea is the subject of study, 

 the type chosen being Henlea fragilis. The history of the genus is 

 first set forth, and previous definitions examined. These are found 

 to be unsatisfactory, and a new definition is proposed. The history 

 of the type is then given, with a detailed account of the external 

 characters and internal organs. This leads up to the definition of 

 the species, and the discussion of its systematic position, which is 

 shown to be related on the one hand to Henlea hibernica Southern, and 

 on the other to the American species Henlea moderata Welch. 



The group of worms known as Enchytraeids is a large and important 

 one. While the species are, on the whole, known to be of great service 

 in relation to Agriculture, there has for some time been a suspicion 

 that in certain cases they are injurious to plants, and these studies arise 

 out of efforts now being made to determine the question of their value. 

 The family name Enchytraeidae is of interest in this connection. By 

 its etymology (eV, in and ^Tpo?, a jloiver pot) we learn that the type 

 was first observed in gardens, and might be regarded pre-eminently 

 as the "pot worm." Later research, however, reveals the fact that 

 the various species and genera included in the family enjoy the widest 

 possible distribution in this country, being found not only in pots and 

 flower borders, but in manure heaps, leaf mould and vegetable refuse 

 of all kinds, from low tide mark on the seashore to the tops of our 

 highest hills. 



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