I30 DISCOVERY REPORTS 



Antarctic localities 



St. 123. Off mouth of Cumberland Bay, South Georgia, 230-250 m., grey mud; i specimen. 



St. 140. Stromness Harbour to Larsen Point, South Georgia, 122-136 m., i specimen. 



St. 149. Mouth of Cumberland Bay, South Georgia, 200-234 m., i specimen. 



St. 160. Near Shag Rocks, 177 m., grey mud, stones, i specimen. 



St. 167. Off Signy Island, South Orkneys, 244-207 m., green mud, 2 specimens. 



St. 170. Off Cape Bowles, Clarence Island, South Shetlands, 342 m., 5 specimens. 



St. MS 68. East Cumberland Bay, South Georgia, 220-247 m., i specimen. 



St. MS 71. East Cumberland Bay, South Georgia, 110-60 m., 6 specimens. 



Remarks on specimens from Falkland Plateau. Probably no known sea star is 

 more variable than Cycethra verrucosa, which is scarcely a species in the accepted sense 

 of the term. Rather it is a complex of a considerable number of intergrading small 

 species and formae, which may be likened to an asymmetrical net. Some of the more 

 conspicuous nodes have received names. But other names apply to single specimens, as 

 in the case of certain variations described by Perrier (1891). We cannot now determine 

 whether these illustrate actual recognizable formae, or are simply "individual varia- 

 tions". 



An obstacle to the establishment of named formae is the difficulty of ascertaining 

 recognition characters which hold good for different ages. Practically all signs fail in 

 Cycethra. Least stable is the breadth of ray and the size of the disk, though, generally 

 speaking, the narrower the ray the smaller the disk. 



The species, or formae, so ably described and illustrated by Sladen, are recognizable in 

 individuals with narrow, medium, and broad rays. There is a very slender-rayed forma 

 electilis which may represent a valid forma distinct from electilis. Similarly, 7utida occurs 

 in a broad-rayed form, quite different from Sladen 's figure. There are large specimens 

 combining the characters oi pinguis and nitida. 



Koehler (1923, p. 61) gives an extended discussion and his figures are a contribution. 

 Yet little real progress will be made until one person can assemble and compare all 

 available material with the type specimens. Koehler has illustrated a slender-rayed 

 forma nitida (1923, pi. 7, figs. 5,11) which is (to the extent of the figures) closely similar 

 to a specimen from St. 55, having R 65, r 18 mm. (R more than 3r). The actinal surface 

 of our specimen is clearly not that of nitida, but of electilis. The adambulacral armature is 

 also that of electilis. Three other examples from this station are similar to Perrier's 

 Lebrunaster paxillosiis {vide infra). 



Before any final assignment of names can be made it will be necessary to determine the 

 type forma, namely, forma verrucosa; whether this includes forma simplex Bell; whether 

 simplex includes, possibly, forma electilis Sladen, or any of the seven new formae 

 described by Perrier in 1891. 



In the list of localities I have assigned most of the specimens to the "nearest" of 

 Sladen's three categories — pinguis, electilis, nitida, using adambulacral armature, actinal 

 plates, and abactinal plates, but not proportions which, as stated above, are apparently 



