Eisenia foetida exists in two races which some taxonomists have separated into species
[see referene (1)]. These are morphologically similar, but one, E. foetida foetida, has a typically
transverse striping or banding on the segments and the other, E. foetida andrei, lacks this and
has a variegated reddish colour. Where possible E. foetida foetida should be used. Other species
may be used if the necessary methodology is available.