1892.] OF THE GENUS PERlCHiETA. 159 



sketch does not show the prismatic colours, which were very evident. 

 The hinder part of the body is extremely transparent and of a pale 

 brown colour ; the blood-vessels and the paired septal glands were 

 quite clearly visible through the thin integument. The last dozen 

 segments or so are yellow-coloured ; beyond the clitellum, which is 

 grey, is a patch of yellow due to the prostate. 



The activity of this species is quite on a par with that of other 

 Perichsetes, and it possesses the same power of everting the buccal 

 cavity that I have referred to in the case of Perichceta indica '^ and 

 the other species described in the present paper. M. Vaillant has 

 also figured the same protrusion of the huccal cavity in Perichceta 

 posthuma. In PerichcBta sinensis the length of the fully everted 

 buccal cavity was quite equal to that of the first three segments of 

 the body. 



The length of the species is 126 mm,, the circumference at the 

 viiith segment 10 mm. 



The individual with the above measurements had 1 04 segments. 



The clitellum, as is occasionally the case, does not coincide exactly 

 with the limits of the three segments (xiv.-xvi.) of which it is com- 

 posed ; it begins after the furrow separating segments xiii./xiv., and 

 ends before the intersegmental groove xvi./xvii. I could discover no 

 setse upon it. 



The oviducal pore is single and median upon segment xiv. 



The atrial pores lie upon segment xviii. 



Genital •papillae. — There are two large sucker-like papillae of 

 circular outline lying between segments xviii./xix. ; each is placed a 

 little to the inside of (and of course below) the atrial pore of its own 

 side. 



The spermathecal orifices were not visible. 



As to the internal anatomy, this species shows the usual characters 

 peculiar to the genus Perichceta. 



There are a pair of cceca in the usual position. 



There are four pairs of spermathecce lying in segments vi., vii., 

 viii., and ix. In several individuals which I dissected the proportions 

 between the pouch and its single diverticulum, as well as the shape 

 of the diverticulum, varied. The normal condition appears to be for 

 the diverticulum to be quite as long as the pouch ; like the pouch it 

 consists of a distal sac where the spermatozoa are retained and a 

 narrowed duct. The pouch itself contained no spermatozoa, only a 

 quantity of material presenting the appearance shown in the accom- 

 panying drawing (Plate X. fig. 3) ; it is of a fluid consistency 

 and contains m.inute granules as well as spherical bodies ; the 

 drawing, I should say, represents the contents of the pouch of a 

 living worm. The diverticulum frequently shows a beaded appearance 

 represented in fig. 4 ; in one case the upper end of the diverticulum 

 was divided by constrictions into seven spherical chambers full of 

 sperm ; quite as often the diverticulum was tubular and of equal 

 calibre throughout, except of course the proximal end, which is always 

 narrower. My investigations upon the living worm, which I had 

 1 P. Z. S. lo£. cU. 



