] 88 Transactions. 



The ' body " contains about 40 segments, biannulated, and much 

 compressed. I did not count the segments in the tails, but they are very 

 much more numerous, and are about the length of one annulus, and are 

 uni-annulated. The two tails are symmetrically placed, as Kirk's figures 

 show, and are separated by a narrow area at the hinder end of the body. 

 The two rows of chaetae of the right and the two rows of the left side are 

 continued on to the two tails respectively ; while on the inner side of each 

 tail two additional rows of chaetae make their appearance, though exactly 

 at what point they commence it is impossible now to say, owing to injuries 

 at their bases. 



Kirk states that " the anal aperture is situated immediately at the 

 posterior end of the thick portion, and between these two limbs or tails."' 

 I am unable to confirm or to refute this statement, though from analogy 

 with other cases I doubt whether it is the case here. At any rate, I must 

 correct the statement that follows : ' ' There is no aperture in the end of either 

 limb, though there is a spot which at first sight gives the impression that an 

 opening is present." In this instance " first thoughts " would have been 

 best, for there is an actual perforation at each end, and an incision into the 

 tail shows that the intestine is continued into it. This is quite what is to 

 be expected, for in all cases which have been dissected, as Robertson was the 

 first to show, the internal organs are, like the body- wall, bifurcated. 



In short, this specimen is very similar to most of those that have been 

 described, except that the body is much shorter than the tails, for generally 

 the bifurcation occurs nearer to the hinder end. 



Korschelt has suggested that in these cases, with approximately equal 

 tails, the bifurcation is due to an embryonic process — a kind of twinning. 

 He refers to a young individual of Allolobophora subrubicunda, which he 

 removed from the cocoon, being bifurcated, and was therefore not the 

 result of injury, but was probably due to the partial division of the ovum 

 or embryo. It is known that in some species of Lumbricus the ovum does 

 divide into two embryos at an early stage of its history ; in these instances 

 of bifurcation, then, the division has been incomplete. 



III. Mr. T. W. Kirk was good enough to send me a water-coloured drawing 

 of a living bifid worm with two approximately equal " tails " and very similar 

 to that described by Robertson, Bell, Williamson, and others. Unfortu- 

 nately, it has not been identified, but it looks to me like L. rubelhis. It 

 was found in Rangitikei. 



References. 



Andrews, E. A. American Naturalist, vol. 26, 1892. 



Bell, F. J. Annals and Mag. Nat. Hist., ser. 5, vol. 16, 1886. 



Korschelt, E. Zoolog. Anzeig., vol. 43, 1914. 



Robertson, C. Quart, Journ. Micro. Sci., vol. 7, 1867. 



Williamson, H. C. Annals and Mag. Nat. Hist., ser. 6, vol. 13, 1894. 



