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



1. Spongolonche conostyla, n. sp. (PI. 48, fig. 7). 



Spongy disk circular, with irregular framework, without concentric rings. Both opposite radial 

 spines conical, about as long as the radius of the disk, and four times as long as broad at the 

 base. Margin of the disk nearly smooth. 



Dimensions. Diameter of the disk 016 ; length of the radial spines 018, basal thickness 0'045. 



Habitat. Pacific, central area, Station 268, depth 2900 fathoms. 



2. Spongolonche amphistyla, n. sp. 



Spongy disk circular, with four to six concentric rings in the inner part, with quite an irregular 

 framework in the outer part. Both opposite radial spines cylindrical, twice to three times as long as 

 the diameter of the disk, at the base about as broad as two meshes of the framework. Margin of 

 the disk ciliated. 



Dimensions. Diameter of the disk 0'2 ; length of the radial spines 0'4 to 0'6, basal thick- 

 ness O'Ol. 



Habitat. Pacific, central area, Station 271, depth 2425 fathoms. 



Genus 256. Spongotripus, 1 Haeckel, 1881, Prodromus, p. 461. 



Definition. S pongodiscida with three solid radial spines on the margin of 

 the circular or triangular disk. 



The genus Spongotripus is characterised by three marginal spines, which are 

 commonly regularly disposed, more rarely in a bilateral or an irregular manner. It corre- 

 sponds to Trigonocydia among the Coccodiscida, to Tripodictya among the Porodiscida. 



Subgenus 1. Spongotripodiscus, Haeckel. 

 Definition. Radial spines of equal size and distance ; triangle regular. 



1. Spongotripus regularis, n. sp. 



Spongy disk circular; three radial spines on its margin of equal size and equidistant, strong, 

 conical, about as long as the diameter of the disk, and five times as long as broad at the base. 

 Dimensions. Diameter of the disk 015 ; length of the spines 016, basal breadth 0'03. 

 Habitat. Pacific, central area, Station 272, surface. 



1 Spongotripus = Spongy disk with tripod ; airiyya/;, r^'rov;. 



