20 



IVAR ARWIDSSON, SYSTEMATIC NOTES ON SOME MALDANIDS. 



ocelli are situated in a somewhat extended group on each side immediately beneath 

 the foremost part of the börder and reach behind somewhat beyond the (contracted) 

 mouth; ef. fig. 15 and text-fig. 5. Upon the cephalic borders and immediately in front 

 of them single ocelli are visible as well as also on the lower side of the head, furthest to 

 the sides, in both cases in immediate continuation to the other groups. Between the 

 posterior part of the cephalic borders or the greatly reduced cephalic plate (still smaller 

 than in L. johnstoni) and the anterior limit — which as a matter of fact is rather uniform 

 all round — of the l st setigerous segment there is no trace of any intervening limit. 

 The 2 nd to at least the 5 th setigerous segments show distinct indications of a collar, 

 most strongly developed on the 4 th — 5 th segments. The 8 th setigerous segment, which 

 has parapodia in its posterior part, bas a distinct anterior limit running on the lower 

 side immediately in front of the large glandular field, but laterally and dorsally some- 

 what farther behind, much the same as in the previous species (ef. in addition figs. 

 16—18). 



There are 5 complete specimens at hand, 4 of which have 24 and one 25 setigerous 



Text-fig. 5. Leiochone leiopygos. — Part of head from 

 the right side. Ocelli. 29.1. 



Text-fig. 6. Leiochone leiopygos. — Uncinus (third from 

 above) from the 2 nd setigerous segment. 240: 1. 



segments. The hindmost 3—4 segments decrease fairly rapidly in length. They are 

 followed by a very characteristic part, consisting of two short, achaetous segments (fig. 

 19). The posterior one of these is specially short and passing evenly into the posterior 

 end, which increases uniformly in width, at least in a contracted condition, and supports 

 the anal cone. The achaetous segments, except their glandular bands, are only slightly 

 marked off , without any external traces of parapodial remains. There are no anal cirri 

 at all; the posterior edge, running all round, is of ten rather strongly projecting in con- 

 tracted specimens, while the anal cone begins, so to speak, somewhat inside the same 

 edge. In this way in strongly contracted specimens a circular groove separates the 

 edge and the cone. The anal cone has a rather pointed anal peg, passing dorsally into 

 a rounded body or swelling, which in fig. 19 just projects a little from the anal opening. 



The nephridia, which open out distinctly behind and somewhat below the lowest 

 uncini, are situated in the 6 th — 9 th setigerous segments. 



Epidermal glands. Besides more or less scattered glands över practically 

 the whole body the following patches appear more or less conspicuously (ef. also figs. 

 16—19). The keel of the head has strong glands, especially in front. The anterior band 



