124 



FISHER 



exposed surface of plate parallel with median suture. Inner 

 spine of superficial series largest, and like the rest, slender, 

 pointed, tapering. All spines decrease in size toward outer 

 end of plate. Innermost marginal spine situated nearer peri- 

 stome than is the enlarged inner superficial spine. 



Madreporic body between second and third lateral rows of 

 paxillse, and hidden by them. 



Type, No. 21928, U. S. Nat. Mus. Type locality, Alba- 

 tross Station 2970, vicinity of Santa Barbara Islands, in 29 

 fathoms, on fine gray sand and mud. 



Remarks. — This species has the general form of L. lorioli 

 Meissner (Mazatlan), but has longer arms, which are more at- 

 tenuate distally. L. ludwigi lacks the conspicuous sharp spinules 

 which are present in many of the lateral abactinal paxillse of 

 lorioli, and the latter has no abactinal pedicellariae, such as are 

 very characteric of the present species. Another character 

 which separates ludwigi from both lorioli and bellonce Lutken 

 is the presence of prominent pedicellariae on the actinal inter- 

 mediate plates of interradial region and proximal half of ray. 

 Details of adambulacral armature differ in all three forms. 

 L. ludwigi differs from L,. quinaria in having much longer nar- 

 rower rays, no scattered and abundant abactinal pedicellariae 

 over the midradial region, and in having 3-jawed, not 2-jawed, 

 actinal pedicellariae. The abactinal pedicellariae of quinaria 

 are low, and of the bivalved form of some Goniasteridae. The 

 adambulacral plates also have 2-jawed pedicellariae in quinaria. 



Named for Prof. Hubert Ludwig. 



LUIDIA ASTHENOSOMA Fisher, new species. 

 This fragile creature bears a close resemblance to L. sarsi 

 Diiben and Koren, of northern Europe and the Mediterranean, 

 and may be looked upon as a north Pacific representative of 

 that species. None of the specimens are as large as L. sarsi 

 is known to grow. The California species differs from sarsi 

 in having very small, abactinal, 2-jawed (rarely 3-jawed), gran- 

 uliform pedicellariae scattered along the medioradial area, with 

 larger ones, sometimes, on the regular lateral paxillae, and on 

 upper end of inferomarginal plates. The inferomarginal spines 



