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Show 806 MR. F. E. BEDDARD AND MISS FEDARB [June 20, genital papillae and spermathecae iu Perichceta and the existence of such a connection in Lumbricidae seems to show that physiologically the genital papilla? of Perichceta are different from the tubereula pubertatis of the Lumbricidae. Out of our examples only six had spermathecae, and in every one of these individuals the arrangement of these was asymmetrical. Fig. 1. ^ -^ , «»rj Spermathecal segments of Perichceta biserialis. SP., spermathecae ; N., nerve-cord. The following is a tabulated statement of the number and arrangement of the organs in question :- Segment vi. Segment vii. Ex. 1 3 left, 0 right. 4 left, 0 right. Kx* 2 1 left, 0 right. 1 left, 1 right. Ex. 3 3 left, .J right. 0 left, 1 right. Ex- 4 0 left, 0 right. 0 left, 1 right. Ex. 5 0 left, 0 right. 0 left, 1 right. Ex* 6 0 left, 2 right. 1 left, 1 right, In defining the species, then, ought one to regard the presence and if the presence, tbe irregularity, or on the other hand the absence, of spermathecae as a specific character? Some variations in structure among earthworms have been already noticed : but there is only one case (perhaps two) which is .so striking as that to which |