806 



MR. r. E. BEDDARD A^D MISS ITEDARB 



[June 20, 



genital papillae and spermathecae iu Perichceta and the existence of 

 such a connection iu Lumbricidfe seems to show that physio- 

 logically the genital papillae of Perichoita are different from the 

 tubercula pubertatis of the Lumbricidae. 



Out of ova- examples only six had spermathecae, and in every one 

 of these individuals the arrangement of these was asymmetrical. 



Fig. 1. 



Spermathecal segments o( PerichcBta biserialis. 

 SP., sperm athecEe ; N., nerve-cord. 



The following is a tabulated statement of the number and arrange- 

 ment of the organs in question : — 



Segment vi. Segment vii. 



Ex. 1 3 left, right. 4 left, right. 



Ex. 2 1 left, right. 1 left, 1 right. 



Ex. 3 3 left, 3 right. left, 1 right. 



Ex. 4 left, right. left, 1 right- 

 Ex. 5 left, right. left, 1 right. 



Ex. 6 left, 2 right. 1 left, 1 right. 



In defining the species, then, ought one to regard the presence, 

 and if the presence, the irregularity, or on the other hand the ab- 

 sence, of spernuitheciB as a specific character? Some variations iu 

 jstructure among earthworms have been already noticed: but there 

 is only one case (perhaps two) which is so striking as that to which 



