THE BIONOMICS OF ENGLISH OLIGOCHiETA 21 



in ponds and ditches, streamlets and rivers, estuaries and back- 

 waters makes them exceedingly dainty food for fishes, ducks, 

 waterfowl, and other forms of life. They multiply with aston- 

 ishing rapidity when once they have established themselves 

 in a suitable locality, and are able in a very short time to 

 convert the worthless refuse on which they feed into living 

 matter suitable for the sustenance of animals which can be 

 utilised as human food. 



The Claim of Pachydrilids to Research. — When we remember 

 that there are possibly a hundred different species of Pachy- 

 drilus in Great Britain, that they reproduce with great rapidity, 

 and may under suitable conditions be found in untold myriads ; 

 and when we further reflect that they have never yet been 

 shown to be injurious to man or to plant life, but that they 

 act as nature's scavengers wherever putrid and decaying 

 material is to be found, aerating the foul ooze in which they 

 flourish, and supplying fish and fowl with wholesome food, 

 it will surely be admitted that their task is a beneficent one, 

 and that the Pachydrilids deserve much more attention than 

 has hitherto been bestowed upon them in this country. 



Conclusion. — We have in the foregoing remarks endeavoured 

 to establish the following points : 



1. The Pachydrilids are a group of Enchytraeids possessed 

 of red blood. They are divided into two genera, Lumbri- 

 cillus and Marionina, and are known to number fifty or sixty 

 species. 



2. They are found wherever moist decaying matter accu- 

 mulates — by shore and backwash, in ponds, ditches, streams, 

 and rivers, and especially among sewage. 



3. They are never injurious to man. 



4. Their mission is to purify ooze, oxygenate the mud and 

 slush in which they flourish, disintegrate decaying material, 

 and finally surrender their lives as a delicate aliment for 

 creatures which serve as human food. 



Bibliography 



1. 1 86 1. Claparede, Memoires de la Societe de Physique et d'Histoire naturelle 



de Geneve. Quarto. Geneva. Vol. xvi. i. pp. 75 et seq. 



2. 1916. Friend, Irish Naturalist, vol. xxv. p. 22. 



3. 1912. Lederer, American Journal Public Health, and other papers. See 



No. 12, pp. 207-8, 



