Oligochaeta.] 



SUBANTARCTIC ISLANDS OF NEW ZEALAND. 



267 



and P. hologynus, consists of several groups of long club-shaped cells, whose necks 

 pass through the epidermis in separate bundles. It is no doubt functionally a pro- 

 state gland. The anterior sperm-duct opens in front of it, the posterior duct near 

 its hinder margin. 



There is a paired sperm-sac in 9 ; a second pair arises as an evagination of septum 

 11/12, and extends through at least segments 12 to 19, the last segment to be in- 

 cluded in the series of longitudinal sections. 



There are two pairs of ovaries — in 12, 13 — and the oviducts are provided with 

 large funnels, opening at 12/13, 13/14. A pair of ovisacs lies in 13 and 14, which 

 are occupied by large eggs. 



A pair of sfemathecae ; each is a long pjrriform sac, which starts from the pore 

 at 6/7 as a narrow short muscular duct, but soon widens out into the ampulla, which 

 curves backwards as it passes below the oesophagus into segment 8 ; here it crosses 

 over to the opposite side, and ends in an enlargement. 



Localities. — Auckland Islands: (a.) Camp Cove magnetic station; two; 

 (W. B. B.). Adams Island: one; (Speight). [I have also a specimen which I 

 collected some years ago on Stewart Island.] 



Remarks. — The species is so similar to P. hologynus, Mich.,* from Western Aus- 

 tralia, that were it not that the second male pore, which is undoubtedly on the 11th 

 segment in this new species, is according to Michaelsen on the 12th, close to the 

 anterior margin, I should have placed it in that species. It agrees with it and with 

 P. ignatovif in possessing the copulatory gland inside the 11th and 12th segments. 

 In this genus we have exemplified a most interesting shifting of the male pores, so 

 that the difference between it and Haplotaxis is reduced to a minimum. In the 

 typical species, H. gordioides, the male pores are on successive segments, and the 

 two pairs of female pores are at 12/13, 13/14, as in P. hologynus and P. aucklandicus ; 

 but the remaining species of Pelodrilus have only one pair of female organs, while 

 Haplotaxis heterogyne, Benham,J has also but one pair of ovaries. As to the male 

 pores, in P. violaceus they are both on 12 — the anterior at the front, the posterior 

 at the back of the segment. In P. ignatovi and P. africanus the anterior pore is in 

 11, at the front margin, the posterior at the front of 12; in P. darlingensis the 

 anterior pore has moved back to the middle of the 11th; in P. hologynus it has 

 reached the hinder margin of the segment ; while in P. aucklandicus the posterior 

 pore has moved forwards into the 11th segment, so as to be quite near the 

 anterior pore. 



The study of this genus seems to be opposed to the Mutationists, for there is 

 quite a gradual transition — no sudden jump from one condition to another. I am 

 almost inclined to unite the two genera, Pelodrilus and Haplotaxis, as I lay less stress 

 upon the importance of the gizzard than does Michaelsen : surely it is one of those 

 characters that are readily affected by the habits of life. 



* Michaelsen, Die Fauna S.W. Austral., bd. i, Oligochaeta, p. 136. 



t Michaelsen, Verhandl. Naturwiss. Vereins, 1903, p. 3. 



% Benham, " On a New Species of the Genus Haplotaxis " Quart. Journ. Micr. Sci., xlviii, p. 299, 



1904. 



