542 FLORENCE BUCHANAN. 



one the regenerated part was attached quite regularly to the 

 rest of the animal. This of course shows very little, as it may 

 have been that in all these cases the body of the animal had 

 been broken off symmetrically previous to regeneration, and 

 one could only expect to get asymmetry where the body had 

 been broken in a plane not at right angles to the long axis of 

 the body. The one specimen that I have seen asymmetrical 

 at the point of juncture of the regenerated and main portion 

 of the body is the No. 5 of the Australian Amphinomes, where 

 the anterior eleven and a half segments have been regenerated, 

 and the half-segment on the right side is apparently the first 

 of the new segments. It would be interesting to know whether 

 the species or genera in which asymmetrical variation particu- 

 larly occurs are especially remarkable for their power of 

 regeneration. Even if the intercalation of half-segments were 

 shown to be due to regeneration, it would still remain to be 

 shown that the spiral arrangement is likewise due to it. The 

 fact of spirals occurring in Pentastomum, where, as far as we 

 know, regeneration does not take place, seems to me against 

 this hypothesis. It would be very interesting to make experi- 

 ments on the living animals of those species in which irregular 

 segmentation is common with regard to regeneration of lost 

 parts, and also to watch their development. 



In conclusion, I should like to thank Professor Weldon, in 

 whose laboratory I am working, for his kindness in giving 

 advice with regard to this and other work. My thanks are 

 also due to the authorities of the British Museum for kindly 

 giving me access to their collections during the last few years ; 

 and to Mr. Stewart, of the Royal College of Surgeons' Museum, 

 for letting me examine the Polychaetes which are in the 

 possession of the Museum.^ 



' Au interesting paper by T. H. Morgan on the same subject as the above, 

 but dealing chiefly with Oligoclisetes, has recently appeared in the ' Journal of 

 Morphology,' vol. vii, Nov., 1892, pp. 245 — 251. As that number of the 

 journal had not arrived here when my paper was sent to press, I liave been 

 unable to introduce the results contained in it ; but the editor of this journal 

 kindly called my attention to it on receiving my manuscript, and 1 give the 

 reference for the convenience of those interested in the subject. 



