ON THE NEMATODES OP THE COMMON EAETHWORM. 605 
On the Nematodes of the Common Earthworm. 
By 
Oilbert E. Johnson, M.Sc.(Birni.), 
University of Binninghain ; Board of Agriculture and Fisheries 
Research Scholar. 
(Stiidies from the Research Department in Agricultural Zoology, 
University of Birmingham.) 
With Plate 37 and 2 Text-figures. 
Contents. 
Introduction .... 
PAGE 
. 605 
OccuiTence .... 
. 609 
Cultural Methods 
. 612 
Identification .... 
. 618 
Confusion of Two Species tmder one name 
. 619 
Anatomy .... 
. 623 
Questions of Sex .... 
. 627 
(1) Analysis and Character of Reproduction 
. 627 
(2) The Sex Ratio 
. 635 
Life-History .... 
. 637 
(1) Investigation of Problems relating to the Life-Cycle 
. 637 
(2) Probable Course of the Life-Cycle 
. 647 
Summary of Principal Results 
. 649 
Introduction. 
(1) Survey of the Literature. 
It has long been a matter of common knowledge that 
larval nematodes inhabit the common earthworm, Lum- 
bricus terrestris, Linn. They are found both in the 
coelom and in the nephridia. Those occurring in the coelom 
