40 Transactions. 



The Nephridia. — From the 2nd to the 14th segments, inchisive, the 

 nephridium is represented by a conspicuous tuft of minute looping tu])ules 

 arranged in such a way as to form a sort of " rosette " close to the nerve- 

 cord and occuj^ying nearly the whole length of its segment. It is thus 

 a more or less rounded or quadrate mass of tubules. These tufts are 

 much larger in the more anterior segments, and in the 2nd, 3rd, and 

 4th seem to represent the entire organ, but farther back one sees that 

 the tubules are not confined to these tufts but extend outwards along the 

 body-wall for a short distance as a linear series of isolated loops near 

 the septa (fig. 7). In about the 7th-llth I believed that under a high- 

 power dissecting-lens I could detect a duct or tube passing outwards, 

 and ending apparently on the body-wall about half-way up the side 

 of the body. I therefore cut out, stained, and mounted a portion of 

 the side of the body, including the segments 7-11, in the hope of being 

 able to satisfy myself as to the locality of the pore ; but I was unsuc- 

 cessful. The body- wall is too soft to allow such a small aperture to be 

 recognized. 



I then mounted the cuticle of these segments, but was no more 

 successful, for, though the large spermathecal pores and the linings 

 of the chaetiferous follicles are perfectly evident, there is no pore that I 

 could interpret as being the nephridiopore. 



Sections were equally useless, owing, as I believe, to the soft condition 

 of the specimen. 



To continue the internal appearance : The dissolution of the tuft of 

 the tubules, which commences about the 7th segment, continues till at the 

 15th almost all the loops are arranged in the linear series (fig. 8), and by 

 the 17th I fail to see any tuft or rosette. At the 20th I am unable to 

 detect any loops under a lens, but by picking up at random the tissue 

 that lies between the septa I find under the microscope that it consists 

 of minute nephridial tubules with accompanying blood-vessels. 



I was unable to detect any funnel, but the poor state of the tissue 

 has rendered it difficult to make as thorough an investigation on this 

 important point as is necessary. 



However, it is clearly, 1 think, a " meganephric " worm such as I have 

 previously described. 



Locality. — D'Urville Island. 



Remarks.~The genus Perieodrilus (which Michaelsen has separated 

 from my Plagiochaeta) (4) is so far confined to the mountains of the 

 West Coast : it is therefore not surprising that a representative occurs 

 in this island. 



It is evident that the present species is nearly related to P. montanus 

 and to P. ricardi (5), but from each it differs in one or more features. 

 Externally its coloration recalls that of the former, as also in the con- 

 centration of the nephridial loops near the ventral region of the body (6) ; 

 but in P. montanus the gonads are situated on the posterior wall of their 

 segments, in P. ricardi they are on the ventral wall midway between the 

 septa. Only in P. lateralis are they in their normal anterior position as 

 in the present species, but in that worm there are no oesophageal glands 

 and only two pairs of sperm-sacs. In the two other species, while there 

 are four pairs of sperm-sacs, there is only one pair of oesophageal glands. 

 The form of the spermathecal diverticulum Hkewise differs from that in 

 the known species. 



