ECHIURIDAE 249 



Genus Hamingia Koren and Danielssen 

 5. Hamingia arctica Koren and Danielssen. Plate VIII, fig. i. 

 Distribution. Arctic seas. 

 Occurrence. St. 1958, South Shetlands. 740 m. 



One contracted specimen only was secured. The body measured 28 mm. and the 

 introvert 20 mm. The diameter of the body at the widest part was 13 mm. In alcohol 

 the colour was a uniform dull grey-green, and the body wall in the posterior half was 

 sufficiently thin for the rod-like pellets filling the digestive tract to be seen. In the 

 living state, however, the animal was highly coloured as the colour note made at the 

 time of capture indicates: 'body an extraordinarily vivid grass green, introvert very 

 pale weak-milk white.' 



The skin was very tough. The whole animal was contracted and the body was filled 

 with a mass of elongated cylindrical clay pellets of varying size, rounded at the ex- 

 tremities. Owing to the tough nature of the skin and the closely packed mass of clay 

 pellets in the digestive tract, considerable maceration had taken place and the walls of 

 the gut had completely disappeared, as well as some of the other structures. Any 

 comparison of the course and shape of the digestive tract was out of the question. 



Two accounts of the appearance and anatomy of this species have been given : the 

 original one by Koren and Danielssen (1881, p. 20) and a later one by Wesenberg- 

 Lund (1934, p. 7). 



With regard to the Discovery specimen, the body was smooth as described by Koren 

 and Danielssen, not warty at the extremities as in the specimen described by Wesenberg- 

 Lund. The two prominent cylindrical papillae described by Koren and Danielssen 

 were not seen in the Discovery specimen, as was also the case in Wesenberg-Lund's 

 specimens. Two low hemispherical bulges of the body wall appeared on the anterior 

 ventral side some distance apart on the Discovery specimen about 3 mm. from the base 

 of the introvert. They seemed, however, to be accidental bulges rather than related to 

 the papillae in question. They were at some considerable lateral distance from the 

 openings of the nephridia. 



The introvert formed an almost closed tube for most of its length. It was somewhat 

 macerated. The tip was T-shaped and folded. When the tip was unfolded as in the 

 figure, it was seen to be bifid but the arms were comparatively short, much shorter than 

 those figured by Wesenberg-Lund (1934, fig. i), but this may not be significant since 

 the Antarctic specimen was somewhat macerated and further was more contracted 

 than the specimen figured. 



As previously indicated, the digestive tract was completely macerated. The anal 

 trees were also incomplete but seemed quite in keeping with previous descriptions. 

 Two small nephridia were present, opening to the exterior close behind the introvert. 

 In spite of the great difference in distance between the known areas of distribution, 

 the Arctic and Antarctic specimens seem sufficiently similar for them to be linked 

 under the same species. 



