Mr. II. ('. Williamson nn a Hifi'l Earfhimrm. 210 



New York State a live sj)eciincii alxnit ."J iuclie.^ loii^^ witli 

 the posterior end divided tor nearly one tbnrth of its leni^tli. 

 The appcnda<Tes were equal, but each only about two thirds 

 the normal thickness of the body anterior to them. Each 

 appendage possessed a functional anus. The left appendage 

 appears as a continuation of the body, three somites serving 

 to form a gradual transition from the tliicker trunk to the 

 thinner appendage. The right appendage springs from the 

 gaping suture between the trunk and the first of the three 

 transitional left somites; where the origin of the right branch 

 occurs there is a slight constriction not represented at all 

 u])on the left branch. The method of bifurcation seems thus 

 similar to that recorded by Robertson. 



'' Dwight Marsh records a two-tailed eartliworm found in 

 Wisconsin. When alive both tails appear of equal import- 

 ance, but in alcohol one division is markedly constricted where 

 it joins the body and appears as a mere lateral branch. 

 Each appendage lias a branch of the intestine and of the 

 nerve-trunk, as well as functional anus. In alcohol the 

 specimen is only 84 millim. long, the tails each 12 millim." 



Andrews further says that he only knows " of about twenty 

 recorded cases of Annelids with bifid ends. The period at 

 which these monstrosities arise is not well known, whether 

 they were formed in the embryo or were formed in the 

 maturer period of the individual's existence. Yet there is 

 little support for the former supposition, while for the latter 

 we have in two cases good evidence and in many others con- 

 siderable presumption towards this conclusion. Granting for 

 the present that these monstrosities have arisen in late life 

 after the removal of parts of the main axis, or after injuries, 

 we may next inquire how far the two new ends are of equal 

 value, whether the two new parts are equal in origin (as in 

 Robertson's specimen), or whether the one is to be regarded 

 as a subordinate part or lateral outgrowth from the main 

 trunk." 



Dr. Cori * describes a bifid Lunibriculus variegatus which, 

 in the mode of bifurcation, agrees to some extent with the 

 Lumhricus Here described. In the Lmnhriculus^ however 

 each of the three nerve-cords of the trunk — the left, median 

 and right — gives rise to two nerves which become the corre- 

 sponding nerves in the two appendages. 



The Lumbricus described in this article had the posterior 

 portion of the body doubled. The two appendages had 



* Sonderabdruck aus ' Lotus,' 1894, Neiie Folpre, Bd. xiv p. 1-6 

 eg. 3. ^ 



15* 



