POLYNOE SCOLOPENDEINA. 391 



is differentiated from the lateral tentacle beneath. A pair of distinct eyes lie in front of 

 the nuchal collar. The considerably larger anterior pair are scarcely visible from the 

 dorsum, and are situated in the smaller southern forms on the outer border near the end 

 of the peaks, a long interval thus existing between the anterior and the posterior pairs. 

 In the large Hebridean examples these large eyes occupy almost the whole peak, and their 

 direction is more forward than outward. The anterior eyes, as a rule, look forward and 

 slightly outward, and are very conspicuous from the front. A minute lens, less distinct 

 in the larger than in the smaller forms, appears in the centre of the anterior pair. In 

 the preparations the brownish median tentacle is longer than the palpi, tapering from 

 the base to the slight swelling below the filiform tip. It is somewhat densely clothed 

 with short cilia, most of which have truncated tips, only a few being clavate — the 

 latter shape being due to an ovate rather than a rounded tip. The lateral tentacles 

 are of moderate length, and have a slight enlargement below the filiform tip. They 

 are similarly clothed with truncated cilia. The palpi are of average length, and have 

 rows of closely arranged clavate papillae with truncated tips. These are longest and 

 most cylindrical inferiorly, shorter and more markedly clavate superiorly. Smaller 

 forms extend on the tapering extremity of the organ. The tentacular cirri resemble 

 the median tentacle in regard to form and cilia. 



Body linear-elongate, If to 4| inches or even more long, and having from 80 to 

 102 bristled segments. The iridescent dorsum in the larger examples is mottled with 

 reddish brown, which, behind the proboscidean region, is somewhat regularly arranged 

 between the lateral eminences, and by-and-by divided into two by the dark median 

 tubercle which commences about the twentieth bristled foot. These three distinct sets 

 of elevations (two lateral and a median) continue to the posterior end of the body. A 

 ridge-like fold forms a buttress in front and another behind the lateral tubercle, and 

 each bounds the seal-like brownish mottling. Brownish pigment also occurs on the 

 elevations at the bases of the dorsal cirri. The median tubercle is situated towards the 

 anterior part of the segment, the lateral towards the posterior part. In the large forms 

 the reddish hue of the dorsum shines through the scales, and tints the entire region, 

 relieved by the steel-like glitter of the darkly pigmented portions of the scales. In the 

 smaller forms the dull yellowish back is minutely flecked with brown. Every alternate 

 foot in front has a dark brown patch on the eminence for the cirrus. The ventral 

 surface is iridescent, pale brown or dull yellowish in the specimens from the Channel 

 Islands, and posteriorly marked by touches of brown — chiefly on the segmental 

 eminences, which are distinct, and have a large and somewhat clavate papilla which 

 projects backwards between the feet. The segmental papillas become distinct on the 

 sixth foot, and continue nearly to the posterior end. In the centre of the body is a 

 reddish streak. In the large Hebridean forms the under surface and feet are of a dark 

 orange — with the reddish central line — and iridescent. Moreover, in some, broad bars 

 of pigment occur on the ventral surface throughout in more than the posterior half. Two 

 races thus occur, the smaller yellowish-brown southern form, and the reddish-brown 

 Hebridean. 



The body terminates posteriorly in two anal styles, which, like the cirri, are pro- 

 portionally short. 



51 



