424 FAUNA HAWAIIENSIS 



bourhood of the male pores, but side by side, instead of one in front of the other. 

 Setae of clitellum only on i6. 



In a third there was but one papilla to each male pore, and the setae on the 

 clitellum were limited to i6. None of these latter had any anterior genital papillae. 

 A fourth example was 94 mm. in length, with setae only on the last segment of 

 clitellum; the sperm sacs as in the species generally in segments 11, 12, but provided 

 with the small terminal knobs such as I have just referred to in Perichaeta barbadensis. 

 The spermathecae appeared to be in 7, 8, instead of 6, 7. In all the prostates were 

 long and had no terminal bulb. I need not enumerate in detail the various arrange- 

 ments of the genital papillae in these examples from Hong Kong ; but I may state 

 generally that they varied excessively in this particular. There were often two to four 

 papillae on the i8th segment between the male pores; it was very general to find a 

 pair of papillae on segment 19 corresponding in position to the male pores on the fore- 

 going segment. I observed a median papilla on each of segments 6 — 8 in one 

 individual ; one was anomalous by reason of the fact that the 7th segment had no less 

 than six papillae arranged in an irregular line along the middle of that segment. The 

 spermathecae were as a rule two pairs in 6, 7. But this character was not absolutely 

 fixed. One specimen had an additional spermatheca in the 8th segment, but on the 

 right side only. In this individual moreover the generally missing septum 8 was present, 

 a circumstance which Rosa has stated for Perichaeta niorrisi. Among the same worms 

 there were three specimens of rather larger size. One of these was 135 mm. long and 

 was the largest. It has 90 segments. In it the papillae were as much reduced as they 

 ever are in this species. The larger worms with the fewer papillae and three pairs of 

 spermathecae I consider to be the more typical hawayanzis. In this individual (to 

 resume) the sperm sacs had constricted apices ; the spermathecae three pairs in 6 — 8. 

 One papilla only to inside of male pore; setae on 16, those of segments 3 — 7 about 

 enlarged. Obviously the same as this, but a little smaller, was a worm with two 

 papillae by male pore and a single median one on 7. These larger specimens have the 

 duct of the spermiducal gland bent into an U-shape ; in the smaller and more papillated 

 worms the duct is usually slightly curved more in the direction of a large semicircle. 

 If we are to accept this as a species we can find no character not found in examples of 

 the forms already treated of, except that the two pairs of spermathecae may be a 

 segment further behind. This seems to be hardly enough as a character whereby to 

 separate the species. 



With regard to the identity of Perichaeta majiritiana I must chiefly refer to 

 Dr Michaelsen. I may observe however that in the position of the spermathecae and 

 the presence of setae upon one segment only of the clitellum, this supposed species 

 agrees with an individual which I found myself unable to definitely distinguish from the 

 form which I have called Perichaeta niorrisi. 



In two individuals which I refer to this species, and which are not the same that 



