240 SUBANTARCnC ISLANDS OP NEW ZEALAND. [Polychaeta. 



prepared before communicating them to Ehlers I had identified them with Kinberg's 

 species from the similarity in dental formula. 



I have examined a considerable number of this common tube-forming species, 

 of different sizes, from different localities, and amongst them duplicates of those for- 

 warded to Ehlers, and without exception I find that they all present the group of 

 denticles in area III of the maxillary region of the pharynx, although in poorly pre- 

 served specimens, where the cuticle is loosened from the epidermis, and in some 

 individuals where the colour of denticles is very faint, they may easily be over- 

 looked unless one is on the look-out for them and a suitable magnification is used 

 for their study. 



So far as the dentition is concerned, A'^. australis is said to differ from N. 

 magalhaensis, according to the description of the former by Ehlers, in having no 

 denticles in this area III. I thus had my suspicions aroused as to the distinction of 

 these two species, and carefully compared the accounts of the anatomy given by 

 Mcintosh and Ehlers respectively, and I can detect no other differences in these 

 accounts than the one relating to the dentition. 



The relative lengths of the peristomial cirri are, to some degree, a specific 

 difference in Nereis ; and, as Mcintosh says of his Kerguelen specimen that the 

 longest cirrus, which is the posterior superior cirrus, reaches to the 14th foot, 

 while Ehlers in his account of N. australis gives the 9th foot as the length, I 

 thought that possibly this feature might serve to distinguish them. I therefore 

 paid attention to this character, and have come to the conclusion, founded on the 

 figures detailed below, that there is a great range of variation in this character, not 

 due to difference of species, nor only, if at all, to different methods of preservation, 

 nor to locality, nor depending on the length or breadth of the body. All one can 

 say is that the two upper peristomial cirri are much longer than the two lower 

 ones, and that the superior is the longest. 



Other specific characters depend on the structure of the parapodia, their 

 condition in different regions of the body, and the microscopic details presented 

 by the chaetae ; but in all these points the New Zealand worms agree pre- 

 cisely with Mcintosh's account of N. eatoni (that is, N. magalhaensis) and with 

 Ehlers' account of N. australis. I conclude, therefore, that the two species are 

 identical. 



It is curious to note that both Mcintosh, for N. eatoni, and Ehlers, in his account 

 of A^. maqalhaensis, compare and contrast the species described with the European 

 N. dumerilii ; yet Ehlers, when discussing the differences between N. australis on 

 the one hand, and N. dumerilii and N. agassizi on the other, makes no mention of any 

 similarity to N. magalhaensis, nor suggests in any way that Kinberg's species is 

 synonymous with Schmarda's. 



I give below a series of measurements of a number of specimens, to illustrate 

 the range in dimensions and the relative lengths of the peristomial cirri. The length 

 of body varies from 200 mm. (which appears exceptional, and partly due to care- 

 ful preservation in formol) to 40 mm. ; the number of segments from 150 to 62 ; the 

 diameter of body from 5*5 mm. to 3 mm. Of the score or so measured, the majority 

 are 60-65 mm. in length, which may be regarded as the average, with 95-120 seg- 

 ments. 



