The Echinoderm Fauna of South Africa. 241 



LUIDIASTER HIRSUTUS. 



Studer, 1884. GAZELLE Ast., p. 47; pi. 4, figs. la-d. 



This species was originally found northwest of Kerguelen, on 

 sandy bottom, in 130 fms. of water. Its occurrence in South African 

 waters is thus of much interest, though not surprising. The individ- 

 uals before me show a range in size from R = 20 mm. to R = 

 65 mm. but the growth changes are trivial between these two 

 extremes. In the largest specimen, there are not infrequently 3 

 large spines on the actinal surface of the adambulacral plates and 

 there are 2 large inframarginal spines. It is remarkable that Ludwig 

 in his otherwise useful key to the species of Luidiaster (1910. Sitz. 

 K. Preus. Acad. Wiss. Berlin, p. 453) says of hirsutus "untere Rand- 

 platten mit einem Stachel", when Studer distinctly says they bear 

 two long spines. Even in the smallest specimen at hand, there are 

 two such spines on the basal inferomarginals. 



P.P. 18904. 36 40' S x 21 26' E, 200 fms. Gr. s. 3 young specimens. 



P.F. 18913. Same station. 2 adult specimens. 



ASTROPECTIN1DAE. 



This family is represented in South African waters by 10 species, 

 most of which are however continental rather than truly littoral 

 forms. One, apparently new species, is distinctly abyssal. They may 

 be distinguished from each other as follows: 



Keif to the South African Species of Astropectinidae. 



No specialized spines or spinelets on either series of marginal plates 



Leptychastcr kerguelenensis. 



More or less conspicuous spines or spinelets on inferomarginals and often on 

 superomarginals as well. 



Actinal interradial areas more or less extensive; madreporic body hidden by 

 paxillae on its surface. 



Inferomarginals, and often superomarginals also, with single large spinelets. 

 No large spine on actinal surface of adambulacral plates 



Plutonaster intermedius. 



A large erect spine on actinal surface of each adambulacral plate, at 



least distally ..... Plutonaster proteus. 



Inferomarginals with a few insignificant spinelets on each, none on 



superomarginals . ... Dipsacaster sladeni. 



Actinal interradial areas small ; madreporic body small not hidden by paxillae 



on its surface. 



Marginal plates, especially inferior, more or less vertical, at least at base 

 of ray, the vertical height of ray at base being approximately equal to 

 combined height of both series of marginals. 



