75 



microscopical structure is similar to that of other Perichaelidae. The 

 pit, in which the spermiducal pores lie, is due to the absence of 

 the clitellar elements in the epidermis and the faint development of 

 the longitudinal muscular layer in this area. 



The nephridia consist of several loops and open externally with 

 a slender excretory duct, without a coecum; their external pores do 

 not alternate with each other. The nephridia, situated in the seg- 

 ments anterior to the XVIIIth., have their loops higher developed 

 than those situated more backwards. 



21. Perionyx gruenewaldi Michaelsen. 



Java: Tjibodas. 



Sumatra: Manindjau, Singkarah, Fort de Kock. 

 This species, first described by Michaelsen from Sangir, and cha- 

 racterized by the presence of penial setae, can at once be distin- 

 guished from the foregoing species by its colour; the violet-red tint 

 of its dorsal side is obviously separated from the yellowish colour 

 of the ventral and lateral sides , whereas in P. violaceus the tint of the 

 dorsal and that of the ventral side gradually pass into each other. Again in 

 this species the pores of the spermathecae are very noticeable, situated 

 upon a glandular area; in some examples they were surrounded by 

 a brown ring and visible even to the naked eye , whereas in P. vio- 

 laceus they are not distinguishable externally. On the contrary the 

 dorsal pores, very obvious upon the clitellum in P. violaceus, appear 

 to be hardly discernible in this species. P. gruenewaldi also appears 

 to be of a larger size than P. violaceus ; the largest example from San- 

 gir measured 85 mm. in length. Our largest specimen had a length 

 of 75 mm. P. excavatus, agreeing with P. gruetiewaldi and P. viola- 

 ceus in the number of spermathecae, appears to be distinguished by 

 a smaller number of setae (36 à 40), by its spermathecae without di- 

 verticulum and by its globular, undivided prostata. 



