144 DISCOVERY REPORTS 



may have 2 spines on furrow margin and 2 on the actinal surface of plate, or only i 

 furrow spine and i subambulacral. 



The mouth-plates have 4 or 5 marginal spines and 2 or 3 shorter suborals in a parallel 

 series. They are subterete, slightly tapered, bluntly pointed. 



In one specimen from St. 42 the madreporite measures 1-5 by 2 mm. ; in the other it is 

 2-5 by 2-4 mm. ; in that from St. 140 it measures i -5 by 2 mm. This character is therefore 

 unstable, and the disparity between the madreporites of the type of sladeni and of the 

 Shag Rocks specimen is probably without taxonomic significance. 



Although a specimen measures only R 33 mm., the ovaries are well developed and 

 contain eggs 0-75 mm. in diameter. 



Just how to treat this recognizable form is something of a problem. It is as distinct 

 from antarcticiis as is fiisais. Its high paxillae, slender spinelets, and small actinal inter- 

 radial areas appear to relate it to sladeni. But the specimen of sladeni from the Palmer 

 Archipelago complicates the matter since it indicates a range which would reasonably 

 include that of georgianiis. No specimen typical of sladeni has been taken at South 

 Georgia, proper, and it is possible that georgiantis does have some geographical or eco- 

 logical significance. Only more material can answer the question. 



Type locality. St. 42. Oflr mouth of Cumberland Bay, South Georgia, 120-204 n^-' 

 2 specimens. 



Specimens examined. In addition to two from St. 42, a paratype from St. 140, Strom- 

 ness Harbour to Larsen Point, South Georgia, 122-136 m. 



Perknaster charcoti (Koehler) 



(Fig. B, 5-5e;PlateVII, fig. 3) 



Cryaster charcoti Koehler, 1912, p. 33, pi. 2, figs. 8, 9; pi. 3, fig. 8. — 1920, p. 132. 



St. 39. East Cumberland Bay, South Georgia, 179-235 m., grey mud, i specimen (A). 



St. 148. OfT Cape Saunders, South Georgia, 132-148 m., grey mud, stones, i specimen (B). 



St. 149. Mouth of East Cumberland Bay, South Georgia, 200-234 '^•' ' specimen (C). 



The three specimens measure as follows : 



Specimen A, St. 39, R 90 mm., r 34 mm., br 34-39 mm. (specimen pressed flat); 

 specimen B, St. 148, R 51 mm., r 16 mm., br 19 mm. ; specimen C, St. 149, R 102 mm., 

 r 40 mm., br 43-47 mm. 



Specimen B is the only one which is at all comparable to the example oifiiscus, from 

 Kerguelen, in which R = 34 mm. Although B is larger and a light yellowish brown in 

 colour, while fusciis is dark brown, the two are very similar, especially in the features of 

 the actinal surface. The adambulacral spinelets as a rule form a transverse series of 3, 

 precisely as indicated by Sladen in his figure of the type oi fusciis (1889, pi. 97, fig. 4). 

 The furrow spine is strongly compressed, heavily sheathed, and its base occupies almost 

 the entire length of the plate. The second spine is also compressed, but is about three- 

 fourths as long as the furrow spine, while the third is tapered and about two-thirds the 

 length of the second. Just external to the third is a pair of actinal spines which Sladen 



