ON A MONSTROSITY OF THE COMMON EARTHWORM. 293 



XX. 



ON A MONSTROSITY OF THE COMMON EARTH- 

 WORM, LUMBRICUS TERRESTRIS, L. 



BY R. BROOM, B.SC. GLASGOW UNIVERSITY. 



[Read 24th April, 1888.] 



Some years ago I had the good fortune to pick up 

 an earthworm which showed a rather interesting 

 abnormality. I put it in spirit at the time, and it is 

 only recently that I have made a careful examination 

 of it. The whole length of the worm is about 4 inches ; 

 and at a distance of 3J inches from the mouth the 

 body divides into two slightly unequal parts, each 

 of which is furnished with a perfect anus. The 

 longer of the two parts, which measures 8 lines, lies 

 as nearly as may be in the same axis as the rest of 

 the body ; while the shorter, measuring about 5 

 lines, projects out on the left side almost at right 

 .angles to the main axis of the body. 



In front the worm is perfectly normal, the clitel- 

 lum occupying the 29th to the 35th segments as 

 usual. Nothing abnormal is to be observed till the 

 120th segment is passed, when it will be seen that 

 the 121st and 122nd segments are shortened, as are 

 also the two following. On the right side the 122nd 

 is joined in the normal way to the 123rd ; but on 

 the left side these two segments are, as it were, 

 pushed apart, and the first segment of the shorter 

 of the two posterior divisions is fixed in between 

 them, so that this segment is joined in front to the 

 displaced part of the 122nd segment and behind to 

 part of the 123rd. Beyond the 122nd segment, the 

 point where the body divides into the two posterior 

 parts, there are 36 segments in the longer — that is, 

 in the one which lies in the same axis as the front 

 part of the body— and 22 in the shorter. It will 



