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



scarcely broader than the bars. Two polar spines conical, very stron,!,', alioiit half as long as tlie 

 main axis of the shell and three times as long as broad. 



Bimeiisions. — Length of the shell (without spines) 0-2, breadth 0-08. 



Habitat. — Central Pacific, Station 265, depth 2900 fatlmnis ; fossil in the rocks of Barbado.s. 



2. Spongoprutium atractus, n. sp. 



Shell spindle-shaped, twice as long as broad, witli thorny surface. Spongy framework loose, in 

 tlie whole shell of the same structure, with large meshes, eight to twelve times as broad as the bars. 

 Two polar spines angular, pyramidal, very strong, about one-third as long as the shell, and twice as 

 long as broad. 



Dimensions. — Length of tlie shell 0'2, breadth Oil. 



Hahitat. — -Western Tropical Pacific, Station 225, depth 4475 fathoms. 



3. Sjjongojirunum amphicylindrutt, n. sj). 



Shell nearly cylindrical, four times as long as broad, with rough surface. Spongy framework 

 compact, in the whole shell of equal structure, with small meslies, twice to three times as broad as 

 the bars. Two polar spines cylindrical, very large, longer than the shell, and about one-fourth as 

 thick as its diameter. 



Dimensions.^— Length of the shell 0'2, breadth 0'05. 



Hahitat. — South Atlantic, Station 333, surface. 



Subfamily Spongodruppida, Haeckel. 



Definition. — Bpongurida with latticed medullary shell, enclosed by a spougy 

 cortical shell. 



Genus 148. Spongodruppa,^ n. gen. 



Definition. — S p o u g u r i d a with spongy ellipsoidal cortical shell, enclosing 

 a simple, spherical or ellipsoidal, latticed medullary shell. Polar spines absent. 



The genus Spongodrupjya opens the series of Spougodruppida, or of those 

 Spongurida in which the ellipsoidal sjaongy cortical shell encloses a simple or double, 

 latticed, medullary shell. In Spongodruppa, the simplest and prol^ably the ancestral 

 form of this subfamily, the medullary shell is sim2jle and the polar spines absent. 

 It may be derived from Drupiyula by a spongy thickening of the simple latticed 

 cortical shell. 



' Spongodruppa = fipongy olive-fruit ; n-roy/o;, Oi;iiv-a. 



