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the Lumbrici in this respect : they each have six girdle seg- 

 ments ; but while two of them have the tubercula extending 

 over the four innermost girdle segments, the third (O. gracile) 

 has the band along the whole six. Along with this peculiarity 

 we have also a difference of colour, habit, and habitat. Octolasium 

 gracile Oerley is somewhat flesh-coloured, emits no turbid 

 fluid, and is found in wet places ; while O. cyaneum and 

 O. lacteum have steel-blue bodies, clay-coloured girdles, and 

 yellow tails, from which coloured fluid exudes, and are found 

 in gardens and fields, chiefly in ground which is under 

 cultivation. 



Among the Allolobophoras the most constant seems to be 

 A. longa, which shares with L. terrestris the dominancy among 

 British Earthworms. The two are readily distinguishable by 

 the position of the girdle, the colour, and the shape of the 

 prostomium, but were until quite recently constantly mistaken 

 the one for the other. In the case of almost all the other 

 species of Allolobophora variation constantly occurs. Thus 

 A. caliginosa has two forms, which are sometimes so well 

 marked that they might pass for different species ; hence the 

 name turgida applied to one, and that of trapezoides to the other. 

 The green worm is exceedingly variable. Sometimes it is an 

 intense green and very sluggish, so that it might be mistaken 

 for a grub. At other times {forma cambrica Friend) it is just as 

 active, and has a colour resembling that of caliginosa. The 

 mucous worm {Eisenia rosea = mucosa) has well-marked varieties, 

 one of which (macedonica) occurs in England and on the 

 Continent, and might almost pass for a subspecies at times. 

 So among the Dendrobenes we have subriibiciinda and arborea, 

 which have similar peculiarities to those found in the foregoing 

 species ; and while at times they are perfectly distinct, at other 

 times it is impossible for an expert to say whether a given 

 specimen is truly one or the other. If any one wishes to pursue 

 this subject further he will find that Michaelsen, Rosa, Beddard, 

 Eisen, Cognetti, De Ribaucourt, Vejdovsky, and others abound 

 in illustrations and supply abundant material for the most 

 critical biologist. 



Allusion was made above to the genus Allurus, and a further 

 reference may be permitted under this heading. In July of last 

 year (1912), while I was collecting at Hastings, I had the good 

 fortune to find quite a number of Oligochaets which were either 



