^Ir. II. ( '. Williamson on n liijid Earthworm. L*21 



ill the left. The typlilosole was present in Ijotli appendaj^es, 

 as well as in the trunk. The gut was ein[)ty at the junction, 

 which was the only spot at which it was opened. The 

 double nerve-cord in the right was of less diameter than 

 that in the left appendage. No difference was noticed in 

 the thickness of the two posterior portions of the supra- 

 neural vessel. The constriction that was noticed externally 

 on the right appendage at its junction with the body of the 

 worm was not distinctly made out on the intestine of the 

 same at its junction with the main alimentary tract formed 

 by that of the trunk and left appendage. Two rows of 

 nephridia were made out on each of the appendages, no 

 ditl'orciice bi-ing found between any of them. 



'J'he structure of the blood-vessels and gut gave no indica- 

 tion as to which appendage might have been secondarily 

 formed. 



As regards the nervous system, there is a normal double 

 cord in the trunk (fig. 4), The left cord (a) is continuous 

 with that of the left appendage (e), and in a similar manner 

 the right cord {b) forms the outer cord of the riglit appendage 

 (_/). The inner cords of each appendage (<■/ and e) are con- 

 fiuent at the bifurcation and have no connexion with the cords 

 of the trunk. 



The vesiculce seminales, the only portions of the reproduc- 

 tive organs present, were poorly developed. Three only of 

 these were found, where normally there should be four pairs ; 

 one {vsi, fig. 6), which was very small, on the left side of 

 the tenth segment, and one on each side {vs2 and vs^, fig. 6) 

 of the twelfth segment. Of the latter the left-hand one 

 (r.Sg) was much the larger. The fact that on the right side 

 of the body the vesiculae seminales were practically un- 

 developed gives ground for the supposition that the right 

 appendage is the result of asexual reproduction. There is an 

 entire absence of any clitcllum ; in this respect tlie specimen 

 resembles that described by Bell. liobertson found in the 

 worm described by him that the reproductive organs were 

 well developed and normal. It would thus appear probable 

 that asexual reproduction does not account for all cases of 

 bifurcation in earthworms. 



The method of bifurcation in this earthworm differs from 

 that in the specimens recorded by Robertson and Fitch. 

 As already mentioned, in Robertson's specimen each of the 

 lateral appendages commenced by distinct and separate rings 

 applied to the eighty-fifth segment. In the worm described 

 by Fitch the right appendage arose from the gaping suture 

 between the trunk and the first of the three transitional left 



