Oll some PerichsRtidfe from Japan. 763 



Vlllth and IXth Segments, just in front of the circle of setie and to 

 the inside of the spermatothecal pores, are paired papilh« very 

 prominent and circular in outline. 



There are three septa in front of the gizzard which constrict the 

 Oesophagus. The first septum behind the gizzard separates segraents 

 X/XI, as in all the species of Perichceta described here, excepting 

 P. sieboldi. Neue of the septa are specially thickened, although the 

 first four or five are bound together by ligamentous threads, as are 

 the specially thickened septa of other Perichrsta. As to the alimentary 

 canal, the only points in which it ditfers from other species described 

 here are 1) that the large intestine coramences in the XVth segment, 

 and 2) that there are only the usual two caeca in segment XXVI. 

 There are the usual dilated perivisceral vessels in segments X— XIII, 

 and masses of nephridia upon the anterior face of the two first septa. 



The generative System presents characters which serve to 

 distinguish the species. The sperm-sacs are not very large; they lie 

 in Segments XI and XII. The atria are well developed extending 

 through four segments XVII — XX. They are very much broken up 

 into lobules. Round the external orifice of the atria are a few white 

 glands. The ovaries are in the Xlllth segment and the same segment 

 contains the Single pair of egg-sacs. There are two pairs of 

 spermatotheciiB in segments VII and VIII; these organs are of exact- 

 ly the same form as in Perichceta rokugo. In common with, or in 

 the neighbourhood of, the spermatothecse are a few small stalked 

 "capsulogenous glands"; these glands precisely resemble those of 

 Perichceta roJcugo in appearance. On the left side of the body in the 

 Vllth segment two or three of them open by a common pore i. e. 

 the copulatory papilla already spoken of; in the Vlllth segment one 

 gland opens on to the papilla, and another opens with the duct of 

 the spermatothecae. On the right side of the body a Single gland 

 corresponds to each papilla, and another pair of glands unite to open 

 close to, if not in common with, the spermatotheca of segment VIII; 

 one of the glands lies however in the Vllth segment, its duct per- 

 forating the septum. Probably the number and arrangement of the 

 glands varies in individuals. 



A hybrid Perichceta (= P. rokugo + P. sieboldi). 

 The question of hybridity among earthworms has never been 

 treated of; facts have been hithertoo wanting. That interbreeding 

 should occur is probable enough; and perhaps some species showing 



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