270 



THE ZOOLOGIST. 



that double-tailed earthworms are plentiful, but that double- 

 headed earthworms are of rare occurrence, only a very few 

 specimens having been recorded up to 1904. Bifurcation of the 

 head region to an extreme degree is shown by a specimen in the 

 possession of Professor J. A. Thomson, of Aberdeen, who very 

 kindly examined the present specimen. 



Dorsal view. 



Ventral view. 



Contracted. Expanded. 



Positions of heads while burrowing. 



Description of Worm. — The worm, as already stated, was 

 sexually mature, and about nine inches long. The bifurcation 

 was very nearly symmetrical, one head having four complete 

 segments, the other three (vide diagrams). Both heads showed 

 the first segment or prostomium very clearly. Each of the two 

 heads had a mouth — an open lumen — both of which were 

 capable of taking in food. 



