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SCIENCE PROGRESS 



The Worms Studied. — In a recent communication to the 

 Zoologist (April 1911, p. 142) my father, the Rev. Hilderic 

 Friend, has given a complete list of the British Annelids and 

 the system of nomenclature he there uses is adopted here. The 

 worms studied by me were as follows : 



1. Lumbricus rubellus (Hoffm.). The Red worm, from Norfolk 



Broads. 



2. Allolobophora longa (Ude). The Long worm, from Swad- 



lincote, Burton-on-Trent. 



3. Aporrectodea chlorotica (Sav.). The Green worm, from 



clayey soil in Darlington. 



4. Octolasiiim cyaneum (Sav.). From Swadlincote. 



5. Dendrobaena. Species uncertain. This genus includes 



the smallest British Annelids. From Swadlincote. 



Nos. 1, 2, 4 and 5 were kindly identified and forwarded to me 

 by my father, whom I take this opportunity of thanking. 



Relative Density oe Worms. — If worms are thrown into 

 water, they invariably sink, showing that, though not possessed 

 of bones, etc., their density is greater than unity. It was of 

 interest to determine the densities of a few species of worms so 

 that, assuming the value to remain constant for all the Annelids, 

 it might be easy to calculate the volumes of smaller worms 

 whose weights can easily be ascertained but whose volumes are 

 too small to admit of accurate measurement. The worms were 

 washed in gently flowing water, dried as satisfactorily as possible 

 with filter papers and introduced into burettes containing known 

 volumes of water. The difference in volume thus produced 

 could easily be read to 0-05 cubic centimetres, so that the volumes 

 were usually accurate to about 1 per cent. The results obtained 

 are given in the following table : 



The Densities of Worms 



From this it is clear that the average relative density of the 

 Annelids, regarding the specimens tested as fair types, is no. 



