466 THE VOYAGE OF H.M.S. CHALLENGER. 



phacoid shell, seven on its radius ; smaller on the equatorial ring, three on its breadth. Four 

 marginal spines pyramidal four-sided, as long and as broad at the base as the ring. 



Dimensions. Diameter of the disk (with one ring) 014, of the phacoid shell Oil, of the 

 medullary shell 0-048. 



Habitat. South Atlantic, Station 335, depth 1425 fathoms. 



4. Staurocyclia magniducis, n. sp. (PI. 37, fig. 4). 



Coccostaurus magniducis^ Haeckel, 1881, MS. et Atlas (pi. xxxvii. fig. 4). 



Phacoid shell twice as broad as the medullary shell, connected with it by numerous radial 

 beams and surrounded by eight chambered rings, which are divided by one hundred to one hundred 

 and twenty piercing radial beams into small chambers. Pores subregular, circular ; ten on the radius 

 of the phacoid shell, two on the breadth of each chamber. Margin of the disk armed with 

 numerous bristle-shaped radial spines, as long as the breadth of the chambered girdle. Four very 

 large crossed spines, nearly as long as the diameter of the disk, quadrangular, with four dentated 

 edges ; at the club-shaped distal end thorny, as broad as the medullary shell and three tunes as 

 broad as at the narrow base. I name this splendid species in the honour of H.R.H. the Grand 

 Duke of Saxe- Weimar, Carl Alexander, the magnanimous protector of arts and sciences, the rector 

 magnincentissimus of the University of Jena. 



Dimensions. Diameter of the disk (with eight rings) 0'27, of the phacoid shell Oil, of the 

 medullary shell 0'05 ; length of the four crossed club-spines - 2, basal breadth 0'02, distal 

 breadth 0'06. 



Habitat. Indian Ocean, Ceylon, Belligemma, surface (Haeckel). 



Genus 202. Astrocyclia, 1 Haeckel, 1881, Prodromus, p. 458. 



Definition. C occodiscida with numerous (five or more, commonly thirty 

 to sixty) solid radial spines on the margin of the circular disk. Medullary shell 

 simple. 



The genus Astrocyclia exhibits on the margin of the circular chambered disk a 

 large but variable number of solid radial spines, commonly between thirty and sixty. 

 They are the external prolongations of the inner piercing radial beams, which divide 

 the concentric rings of the disk into chambers. All the spines lie in the equatorial plane 

 of the disk. The genus corresponds to Stylodictya in the family Porodiscida. 



1. Astrocyclia solaster, n. sp. (PL 36, fig. 7). 



Phacoid shell two and a half times as broad as the medullary shell, surrounded by four to six 

 regular rings of equal breadth, which are divided by thirty to forty piercing radial beams into broad 



1 Astrocyclia = Stellated circular shell ; tinr^a, xvxluu. 



