NEW SPECIES OP PEEICH^TA. 199 



descriptions of all external features that are of diagnostic value ; 

 even the colour of preserved specimens is of some aid in dis- 

 tinguishing species ; and in order to emphasize the specific 

 characters, I append a " diagnosis " to the description of the in- 

 dividual specimens examined. The lack of this diagnosis in many 

 recent writings renders the matter of comparison extremely 

 laborious ; while, on the other hand, a mere formal diagnosis 

 unaccompanied by more detailed description is insufficient. The 

 addition of careful figures of tlie chief structures is most im- 

 portant, and a comparison with other apparently similar species 

 should not be omitted. 



PeEICH^TA NOViE BEITANNICJE, n. Sp. 



There were fourteen rather stout worms, slightly pointed at 

 each end; of a dark purple-brown colour, without any bands or 

 other markings ; the clitellum is a purer brown, marked by two 

 narrow darker bands encircling the body. The posterior region 

 of the body is only slightly lighter than the anterior region, 

 but the last dozen or so segments, as is not unusually the case 

 in this genus, are quite as dark as, or even darker than, the 

 .anterior end of the worm. The body-wall behind the clitellum 

 is transparent. 



The length of the specimens varies from 75 mm. to 180 mm., 

 the average length being 110 mm., with a diameter of 5 mm. 

 The specimen taken for description measures 130 mm., and 

 consists of 120 segments. 



The male pores are small, circular, and pit-like, situated on 

 slightly raised papillas, oval ia outline (PI. 15. fig. 1 a). Imme- 

 diately behind each papilla, or "porophore" (as I would term 

 this area which carries the male pore and which is usually 

 glandular, to distinguish it from other variable specific " copu- 

 latory papillae "), is a somewhat crescent-shaped depression, light 

 brown in colour {s), occupying the hinder part of segment 

 XTirr. Just in front of the porophore on segment svii., behind 

 the chsetal ring, is a similarly coloured area, rather more elliptical 

 in shape (s). These four marks are very conspicuous, and pos- 

 sibly act as suckers. Purther, on each side of each male pore 

 is a small pit-like depression (p), one mediad and one laterad of 

 the pore : these are arranged, therefore, much in the same way 

 .as in P. purpurea, Benham, from Celebes *, 



* Ann. & Mag. Nat. Hist, xviii. 1896, p. 429. 



