Tin: ViNiNALS 



AND 



MAGAZINE OF NATURAL HLSTOUY. 



[SIXTH SKUIES.] 

 No. 75. MARCH 1894. 



XXIV. — On a Bifid Earthioorm (Lumbricus terrestris). By 

 IIknky C. Williamson, M.A., B.Sc, St. Andrews 

 ]\larine Laboratory. 



[Plato X.] 



The Lumhricus described below belongs to Mr. Thomson 

 Blackford, and was handed to me by Professor M'Intosh, 

 to whom it had been courteously sent by Dr. Fulton, Superin- 

 tendent of Scientific Investigations of the Fishery Board for 

 Scotland. 



The specimen is an earthworm in which the posterior half 

 of the body is double. Each of the posterior portions has an 

 anus. The recorded cases of bifurcation in the species of 

 Lumhricus are few in number; and while that abnormality 

 has been noticed not unfrequently in PolychjBta, still compa- 

 ratively few have been described. Professor E. A. Andrews, 

 of Baltimore, U.S.A., published a list of the references made 

 by different authors to bifurcation in Annelids in ' Nature,' 

 vol. xlvii. no. 1214, Feb. 2nd, 1893. Mr. Robertson, of 

 Oxford, gave the following description of a double earthworm 

 in the ' Quarterly Microscopical Journal,' vol. vii. 1867 : — - 



" The rings of the body presented the usual appearance 

 from the first to the eighty-fifth, where the body divided into 

 tvv^o symmetrical halves, each of which presented the usual 

 appearance of the terminal part of an ordinary worm [PI. X. 

 figs. 8 and 9]. Each of these lateral appendages commenced 



Ann. cL' Mag. X. Hist. Ser. 6. VoL xiii. 15 



