ASTEROIDEA 235 



St. WS 847A. Off Porto Santa Cruz, Argentina, 50° 15!' S, bf 57' W, 51-56 m., 3 specimens, 

 intermediate. 



St. WS 847B. Off Porto Santa Cruz, Argentina, 50° i8f' S, 67° 44' W, 56-84 m., 6 specimens, 



intermediate. 



St. WS 867. 51° 10' S, 64° 15' 30" W, 150-147 m., 2 specimens. 



Typical large examples are very distinct from antarctica by reason of the abundance of 

 large triangular straight pedicellariae, the jaws of which are as broad at base as the height. 

 There is a good representation of apparently fully grown specimens. The largest 

 measures R no mm., r 30 mm., br 25 mm. In addition to the numerous characteristic 

 abactinal straight pedicellariae there is usually an abundance of crossed, distributed as in 

 antarctica; but in a large specimen from St. 92 these are relatively few. The crossed 

 pedicellariae are broader than in antarctica. In the latter species, the rounded end of 

 jaw is 0-26-0-30 mm. broad while in studeri it measures o-35-o-38 mm. In typical 

 studeri the abactinal spinelets are decidedly slenderer and generally obviously more 

 numerous than in antarctica. The actinal papular areas contain 2-4 papulae while in 

 large antarctica there is only i. As in antarctica, in the ventrolateral combs there are 

 3 or 4 (rarely 5) prominent spines, of which the inner belongs to an actinal plate. 



In medium-sized specimens (R 50 mm.) the straight pedicellariae are confined to 

 side of rays, only a very few occurring on the adambulacral furrow face. From Sts. WS 

 91 and WS 92 are 2 series illustrating growth stages from R 11 mm. to R 100 mm. 

 One can be reasonably sure that these are all of one species. Up to R 30 mm. there are 

 no straight pedicellariae ; or at base of ray only i or 2 of a broadly lanceolate form such as 

 is found in antarctica and pediceUaris . 



Without the accompanying adults these small examples would undoubtedly be 

 classified as antarctica, although their abactinal spinelets are more numerous and the 

 crossed pedicellariae very much less numerous than in typical small antarctica. 



The abactinal skeleton is well developed with numerous small irregular meshes. In 

 young specimens the skeleton is rather stronger and the meshes smaller than in corres- 

 ponding sizes of antarctica. The species therefore is in nowise closely related to Lys- 

 asterias perrieri or to other species having a degenerated dorsal skeleton. Koehler who 

 examined and photographed the type rather unaccountably placed it in his " A?tasterias" , 

 which led me to list it as Lysasterias (1930, p. 236). It is, as a matter of fact, very close to 

 A. antarctica and possibly may regularly intergrade with that species at intermediate 

 depths. There certainly is no occasion to make the species the type of a new genus on 

 account of its pedicellariae, as Koehler thought might be necessary. 



Typical specimens oi studeri are found in deeper water than antarctica. The specimens 

 from St. WS 847, 51 to 84 fathoms, are not typical in having fewer and coarser abactinal 

 spines and fewer straight pedicellariae which, in one specimen, are narrower than in the 

 typical form. The very numerous crossed pedicellariae are of the broader type, and 

 actinal papulae 2 or 3 to an area. One of the 3 specimens is the largest, having R 1 10 mm. 

 A large specimen (St. 92, 8 April 1927) is carrying a coalesced mass of eggs 20 mm. in 

 diameter. Each egg is 2-5 mm. in diameter. 

 Type locality. Falkland Islands, 320 m. 



