ANNELIDS. I. 



29 



have the same ease as we know in Admetella, namely that two segments are passed over. The last 

 elytron in H. acanellse is found 011 segment 32, whereafter each of the following rings carry on each 



side a long thread-shaped dorsal cirrus. This part of the animal consists of 17 segments. The anal 

 ring bears two exceedingly long anal cirri. 



In all there are 15 pairs of scales. They do not seem to cover the dorsum thoroughly, but leave 

 a narrow streak uncovered in the middle. 



The head (PI. I, fig. 13) is somewhat broader than long. The median incision is rather narrow, 

 but can be followed almost to the base of the cephalic lobe. The two frontal prominences are distinct, 

 directed forwards and not diverging conspicuously. The eyes are relatively large; the foremost pair 

 somewhat prominent, lens carrying. The hindmost two are situated at a rather long distance from 

 each other near the base of the cephalic lobe. The unpaired antenna is considerably long, somewhat 

 longer than the palps. The paired antennae are about one third of the length of the unpaired antenna. 

 The palps are thick, taper gradually towards the very short terminal filament. The tentacular cirri 

 are somewhat longer than the unpaired antenna. None of these appendages are provided with papilla:. 



The foremost scales are almost circular, the others more 

 ovoid in shape, the hindmost broadly reniform. They are den- 

 sely beset with minute conical bodies arranged in more or less 

 regular rows over the surface of the scale; along the outer edge 

 are found some spiny prominences not very conspicuous and a 

 few thread-shaped papilla?. 



The uotopodial branch of the foot is but feebly developed 

 and only few dorsal setae are present. The neuropodial branch 

 bears a bundle of flabellately arranged setae. The dorsal cirrus 

 is very long and slender and tapers gradually towards the tip. 

 The ventral cirrus is relatively conspicuous in length but rather slender. The segmental papillae are 

 distinct and rather prominent. 



The dorsal setae, of which seldom more than 6 to 8 are present, sometimes only 4 to 5, are of 

 the usual sword-shape with transverse rows of small spines; they are rather straight and relatively 

 strong. The distal part of the bristle is entirely devoid of spines. (PI. I, fig. 9). 



The ventral setae are provided with a rather long shaft, the endblade is relatively short and 

 broad. They ressemble the ventral bristles of Harmothoe bathydomus, but the tip is only inconspicu- 

 ously curved. (PI. I, fig. 8). 



The ventral setae of the first parapodium differ considerably from those in the other feet. They 

 are all much more slender, the endblade relatively much longer; besides, the latter is strongly bent, so 

 that it forms an angle with the proximal part of the bristle. (PI. II, fig. 4). In this parapodium the 

 ventral cirrus is verv lone. 



^r 



fie. 11. 



Harmothoe nivea (M. Sars). 



1863. Polynoe nivea, M. Sars: Oeologiske og zoologiske lagttagelser, anstillede paa en Rejse &c. Nyt 

 Mag. f. Naturv. XII. Christiania, p. 291. 



