Annelids from the Danmark Expedition. 421 



of the Danmark Expedition, I must confess to having no longer any 

 doubt, tiiat the two forms mentioned are separate species, tliougli 

 they are very closely related. On well-preserved specimens thej^ are 

 in general very easily distinguished even from the habit; badly pre- 

 served specimens may offer some difficulty, but in such cases a close 

 examination of the bristles will lead to a definite result. 



hi his work on the Greenland Annelids, W. Michaelsen mentions 

 a female, epitokous specimen of Л^ zouata and is of the opinion that 

 it is the same as Heteronereis arctica Ørsted. It is not easy to say, 

 how far Michaelsen is right here ; there are not many points of sup- 

 port for such a view in Ørsted's description, to my mind. Ørsted 

 writes that "the head is relatively very large". This does not seem 

 to me to agree; rather large we might admit; in any case it is indeed 

 a relative expression based on an estimate, but Ørsted gives a meas- 

 ure: the head should be "just as long as the four following rings". 

 This at any rate does not agree with the individuals brought home 

 by the Danmark Expedition, in which the length of the cephalic 

 lobe is as nearl}^ as possible equal to the total length of the first 

 two rings. Comparing this with Malmgren's figure of the atokous 

 N. zonata the length of the cephalic lobe proves to be shorter than 

 the length of the two first segments together. Comparing the size of 

 the head in the atokous and epitokous individuals of N. zonata, I 

 can find no noteworthy difference. — Ørsted 's figure of the para- 

 podium does not agree with the condition in N. zonata, especially 

 not in the case of the untransformed parapodia (Ørsted 1. с. fig. 65). 

 All four parapodial lobes are here evenly and uniformly rounded; 

 this does not appear in my specimens, where the lobes are pointed, 

 triangular in form. Even if there is the possibility that Ørsted's 

 drawing is not very correct, yet the resemblance between his figure 

 and the condition in Л'^. zonata is far too slight to give any support 

 to Michaelsen's view. It seems to me, that Ørsted's figure agrees 

 far better with the condition in Nereis pelagica, of which I Ьале a 

 large material from the Færoes. In the case of this form I have also 

 used the opportunity for a comparison of the pigmentation — having 

 in mind the question of the specific identity of Л^ zonata epit. and 

 Heteronereis arctica Ørsted — and I have found great individual dif- 

 ferences, both in regard to the tone of colour, which may vary from 

 pale reddish to a strong blue-violet, and to the distribution. I believe, 

 that we should be careful in drawing conclusions with regard to 

 similarity or dissimilarity in this connection. For me the matter 

 stands as follows. There is very little probability, that Heteronereis 

 arctica Ørsted and Л', zonata epitok. are identical, and it is impossible 

 to prove that they are. Malmgren's name N. zonata should therefore 



