26o DISCOVERY REPORTS 



spines, or heavier terminally flattened ones. The superomarginals are intermediate in 

 size between the inferomarginals and the small cylindrical or slightly clavate abactinal 

 spinelets, but are not much larger than the latter. The proximal superomarginal plates 

 carry 2 or 3 spinelets, the distals i spinelet. 



On the marginal and actinal plates are numerous large conical straight pedicellariae, 

 the largest half as long as the inferomarginal spines. The base is broad, the jaws tri- 

 angular with a bluntly pointed tip. On the largest specimens they occur also on the 

 lateral parts of the abactinal area. Very numerous crossed pedicellariae are scattered 

 among the abactinal and superomarginal spines, attached to the plates but not to the 

 spine sheaths. They appear to be absent from the actinal and proximal inferomarginal 

 plates. A few are present on the dorsal part of the distal inferomarginal plates, but are 

 not on pads or spine sheaths. 



This species differs from georgiamis in the extensive development of the actinal series 

 of plates, a second series being present proximally ; in the absence of crossed pedicellariae 

 from the proximal inferomarginal plates; in having more numerous inferomarginal 

 spines, a less open skeleton, and larger straight pedicellariae. 



On account of the oblique series of 3 or 4 inferomarginal spines in addition to at least 

 2 actinals, large specimens resemble Smilasterias, which, however, has gonads opening 

 dorsally, and well-developed actinal papulae. 



Distribution. Tierra del Fuego; Falkland Islands; south of Cape Horn; South 

 Georgia; 99-160 m. 



Genus Smilasterias Sladen 

 Smilasterias Sladen (subgenus), 1889, pp. 562, 578. Type Asterias scalprifera Sladen. 



Diagnosis. Small, 5-rayed forms with compact, reticulate abactinal and lateral 

 skeleton beset with small spinelets ; inferomarginals on ventrolateral border of ray, each 

 with a prominent, oblique comb of 2-6 flattened truncate spines which radiate apart and 

 are without attached pedicellariae ; adambulacral plates with 2-4 slender, often flattened, 

 spinelets, devoid of attached pedicellariae; a series of small actinal plates,^ spiniferous in 

 genotype ; abactinal and intermarginal but no actinal papulae ; adoral carina comprises 

 first pair of postoral adambulacrals which are longer than second pair; crossed pedicel- 

 lariae scattered, not in circlets around spinelets; straight pedicellariae lanceolate, 

 scattered on all surfaces; in addition, sometimes, large spatulate unguiculate pedicel- 

 lariae with curved interlocking tines ; tube-feet in 4 series ; one madreporite ; gonads open 

 dorsally at upper margin of superomarginal plates, near interradius. 



Remarks. The presence of S. scalprifera off Marion Island and in the Falkland region 

 seems to indicate that it is a subantarctic species. The records of triremis from Heard and 

 the Palmer Archipelago point to an Antarctic distribution. Sladen, however, records 

 scalprifera from 75 fathoms off Heard Island, which, to be sure, is shallower water than 

 the record of triremiis (150 fathoms). 



1 Stated to be lacking in S. irregularis Clark, Records South Australian Museum, in, No. 4, 192S, p. 102. 



