36 AUSTRALASIAN ANTARCTIC EXPEDITION. 



Ehlers gives some coloured pictures of this common Antarctic Polynoid, in his 

 account of the National Antarctic Expedition, and of its varieties, in the report of the 

 German South Polar Expedition, above referred to. 



In the " Challenger " report, Mclntosh figures the head and the chsetae of 

 the species and varieties as distinguished by him ; and Willey represents the general 

 appearance of the animal and the characteristic tubercles on the elytra. 



For a full list of the synonmy and literature consult Ehlers (1913). 



The species is evidently extremely abundant in Commonwealth Bay, as 169 

 individuals are included in the collection, obtained from depths varying from 2 to 400 

 fathoms, and it probably lives along the shore also, as Ehlers has noted its abundance 

 along shore at all seasons of the year at Kaiser Wilhelm II. Land. 



It is, as is well known, extraordinarily variable in colouration, and Ehlers has 

 figured several of the more usual types. 



I find large as well as small individuals in which the elytra are colourless, so 

 that the worm has a greyish appearance, though the more typical colour is some tone 

 of brown, usually a chestnut, with or without a purplish tinge. 



In some the elytra are uniformly tinted; in others the pigment is in definite 

 patches, which are either small and scattered irregularly over the surface, or arranged 

 in definite lines parallel to the long axis of the worm ; in still others the patches are 

 so closely crowded together that they produce a nearly imiform darker tone. 



In most cases the " areola," that is the area above the attachment of the elytron 

 to its elytropore, is without pigment. In some individuals a reddish-purple spot or 

 even a violet spot lies behind this areola ; or, again, this is reinforced by an additional 

 purple splash near the posterior external border ; this spot may occur both in pale and 

 in darkly pigmented elytra. 



The upper surface of the elytra is often iridescent, and so adds to the beauty of 

 the worm, giving as it does a bluish tinge to the brown in certain parts of the elytron, 

 according to the angle at which light is reflected from it. 



Further, the body wall is pigmented in various ways, and in various tints inde- 

 pendently of the colour of the elytra. In some specimens the dorsum is almost without 

 pigment, but it is usually crossed by narrow bars of brown or olive, which are confined 

 to the median region of the back. Very frequently there is a tesselated, or chess-board 

 pattern of brown or of olive-green, or of both colours combined, giving a beautiful 

 effeci (fig. 21). In such cases the pigment is in the form of quadrate patches on each 

 side of the middle line on alternate segments, the median line being white ; and in the 

 intervening segments, the sides are pale and transverse bars of pigment cross the 

 middle line. 



But the most remarkable variant is found in the largest individuals, where the 

 entire dorsum is a uniform steel-blue or indigo-blue, or purple (as in Ehlers's fig. 1, 1913), 

 with the bases of the parapods white or pale pink, or of a rather deeper lilac colour. 



