1901.] AND AERANGEMENT OF EARTHWOBMS. 191 



of the worm to protrude considerably beyond the general level of 

 the body. This glandular eminence is of a stronger yellow colour 

 than the surrounding body- wall, and is therefore additionally con- 

 spicuous. The outer setse of the ventral couples are just not 

 embraced by it. It occupies all of segments xix.-xxiv., and the 

 intersegmental furrows are perfectly plain throughout. In P. 

 violaceus I described a somewhat similar modified area of integument 

 upon the middle ventral region of segments xxii. & xxui. : it is 

 interesting to note that Michaelsen has found that in that species 

 the position of the Pubertatspolster may vary from xxiii. or xxiv. to 

 xxxii. or xxxiii., nearly the same area therefore that is continuously 

 occupied in the present species. 



The oviducal ]Jores are very conspicuous upon segment xiv. 

 They lie behind the lateral pair of setse. They are asymmetrical 

 in my specimen ; the left-hand pore is nearer to the middle hue 

 than "the right-hand pore. 



As in other species of Polyloreutus, though the details are not 

 always available in extant descriptions, a number of the anterior 

 sq)ta are 1 hickened. The last of these bounds the xith segment pos- 

 teriorly ; this and the four septa lying in front of it are thickened 

 to a \ery considerable extent ; in front of the first there are two 

 or three' septa which are less pronounced. There is a gradual 

 falling off in thickness in the case of the septa lying behind that 

 which bounds the eleventh segment ; the first of them, like the rest, 

 is thin and diaphanous. It is only the septa in the immediate neigh- 

 bourhood of the gizzard, and which closely enwrap it, that are much 

 tied together by threads of muscle in the way that is prevalent 

 among earthworms. The specially thick septa behind are not so 

 interconnected. 



The nepJiridia are regularly paired and furnished with a terminal 



sac. . T T n -.• £ 



It is perhaps not of importance as assisting in the definition or 

 the species to note the double character of the dorsal vessel in 

 certain segments. A continuously double dorsal vessel is, so far 

 as I am aware, generally a specific and sometimes even (as in Octo- 

 choitus) a generic character. But the fact that in Pontoscolex the 

 dorsal vessel may be double for a segment or two, is perhaps not, as I 

 was inclined to" make it at one time, a specific character distin- 

 guishing P. hawaiiensis. However, in Polytoreutus gregorianus, as 

 in Polytoreutus yt'z7i»cK'«e»sis^ (occasionally), the dorsal vessel is 

 double in segments xii. & xiii. and again more anteriorly in segments 

 viu. & is. . . 



The two halves were only separated for a short distance, again 

 reuniting. The dorsal vessel is particularly stout and congested 

 with blood in the three segments which immediately follow the 

 last strong septum ; and in these segments there are no hearts. 

 The last of the hearts lie in segment xi., and they and the pair m 

 front are the largest of the series. 



1 Beddavd, Quart. Jouru. Micr. Sc. vol. xsxvi (n. s.) p. 240. 



