POLYCH^TA BENHAM. 63 



The dorsal ramus of the foot (fig. 66) is rather shorter than the ventral, and the 

 two diverge at an angle which approaches 90. Indeed, in less well-preserved specimens, 

 this angle is a right angle. The end of each ramus is bluntly pointed and appears brown, 

 especially in those cases in which the membrane has been torn away. The " pinnal 

 membrane " is characteristically developed, and resembles that of T. nisseni Rosa. 

 On the dorsal surface it commences on the base of the foot, some distance proximad of 

 the bifurcation ; its line of origin is undulating, as also is its margin. The membrane 

 Continues round the apex, and only ceases at the angle formed by the two rami. The 

 arrangement of the ventral pinnal membrane is similar, but it is more extensive. It 

 bears two " pinnal glands," which are termed by Rosa the " hyaline " and the 

 " chromophil " glands.* There is no " rosette." The species, therefore, belongs to 

 Rosa's sub-genus Tamopteris. 



The " hyaline " gland is capped by a dark orange or red brown mass of pigment, 

 and is situated just dorsal of the apex of the ventral ramus. It makes its first 

 appearance on the 3rd foot. 



The " chromophil " gland (the " cupule " of Quatrefages) appears as a rounded 

 glandular thickening, differing in texture, as in its pale buff colour, from the surrounding 

 transparent membrane. These glands commence on the 5th foot, and are recognisable 

 as far back as the 20th, beyond which I am unable to detect them. 



The two larger specimens are males, and the young testis is situated in the dorsal 

 lobe of the foot, along the roof of its cavity. 



locality. 



Commonwealth Bay. Pack ice. 



Distribution. Antarctic Ocean, lat. 60 3' South, long. 60' (Quat.). Between 

 Kerguelen and Macdonald Islands (Mclntosh). 



Remarks. This species formed the basis of Quatrefages' account of the genus 

 in his " Histoire Naturelle des Anneles," and his account has been repeated, 

 though recast, by Rosa (1908, p. 312) in his useful monograph of the genus. 

 Quatrefages' specimen had been collected during the voyage to the South 

 Polar Regions of the Zdee (1837-1840), though it is not mentioned in the 

 reports of that voyage. The specimen was imperfect, lacking the hinder end 

 and the long cirri. It is described as being opaque and " maroon coloured " 

 (which agrees probably with the present specimens). Owing to the imper- 

 fections of the type, I have deemed it worth while to enter pretty fully into 

 detail, for the species has not been examined or reported upon since 1865. 

 Quatrefages, in his figure of the " head " (pi. XX, fig. 1) shows the epaulettes 

 as triangular, and, as I have mentioned, it is so when the animal is ill preserved. 

 The foot (Quat., fig. 2) is possibly somewhat distorted, as the angle made by 

 the two rami is greater than it is in well-preserved material. Here, again, I 



Though the gland takes hsematoxylin very strongly, it is not noticeably affocted by alum carmine, which I used. 



