264 DISCOVERY REPORTS 



St. MS 65. 28. ii. 25. East Cumberland Bay, i-6 miles SE of Hobart Rock to i cable N of 

 Dartmouth Point. Net attached to small beam trawl, 18 m. 



S. polita, Pfeffer. 



St. MS 66. 28. ii. 25. East Cumberland Bay, 2} miles SE of King Edward Point Light to i\ 

 cables W x N of Macmahon Rock. Small beam trawl, 18 m. 

 5. polita, Pfeffer. 



St MS 67. 28. ii. 25. East Cumberland Bay, 3 cables NE of Hobart Rock to I cable W of Hope 

 Point. Small beam trawl, 38 m. 



S. polita, Pfeffer; S. pagenstecheri, Pfeffer. 



St. MS 71. 9. iii. 26. East Cumberland Bay, 9J cables E x S to 1-2 miles E x S of Sappho Point. 

 Small beam trawl, 110-60 m. 



S. septemcarinata, Miers. 



GEOGRAPHICAL DISTRIBUTION 



The geographical range of the genus Serolis, with the exception of S. carinata, 

 Lockington, which is recorded as far north as San Diego, CaHfornia, is entirely restricted 

 to the southern hemisphere. 



In the following account the distribution of the species has been considered with 

 reference to the Antarctic Convergence. At this line, which surrounds the Antarctic 

 Continent, there is an abrupt change in salinity and temperature, and it has been found 

 that in some groups of animals (e.g. fishes) there are two distinct faunas, one on either 

 side of it. The line lies roughly midway between Cape Horn and Graham Land m the 

 west, and passes north of the Shag Rocks and South Georgia, then eastward, crossing 

 latitude 50° S at 20° E, passing a Httle south of Marion Island and the Crozet Islands 

 and then through the middle of Kerguelen. The temperature along this line ranges 

 from 0-50° to 3-0° in the winter to 3-50° to 5-50° in the summer. The majority of species 

 of Serolis are confined to shallow waters ; the deep-sea forms are comparatively few in 

 number and have a inuch wider vertical as well as horizontal distribution. 



According to Beddard (18846, p. 82) "the shallow-water forms never pass the 300- 

 fathom limit, nor are any of the deep-sea species known to inhabit shallow water". 

 The study of accumulated data proves that this statement is no longer accurate, for at 

 least two shallow-water forms are now known to inhabit depths greater than 300 

 fathoms. S. pagenstecheri, Pfefll'er, is found in depths ranging from 15 to 970 m. 

 (approximately 530 fathoms), and the new species, S . platygaster , which froin its general 

 characters is more closely related to the shallow-water species, was collected at a depth 

 of 728 m. (approximately 393 fathoms). Further, S. 7ieaera, Beddard, one of the deep- 

 sea species, previously recorded from depths ranging from 600 to 2040 fathoms, is now 

 known to exist in comparatively shallow waters: specimens in this collection occur at 

 depths of 239-300 m. (approximately 130-164 fathoms). 



The shallow-water species fall into four groups : 



(i) Those which are found outside the Antarctic Convergence, off the coasts of the 



