REPOET ON THE RADIOLARIA. 1143 



Genus 502. Tripodiscium,^ Haeckel, 1881, Prodromus, p. 428. 



Dcjinition. — Archipilida (vel Mouocyrtida triradiata aperta) without lateral 

 ribs aud apical horn, with three simple or branched terminal feet. 



The genus Tripodiscium may he derived either from the preceding Tripilidium by 

 loss of the apical horn, or from the nearly related Tristylospyi'is by loss of the sagittal 

 ring and constriction. Some forms of the latter genus can scarcely be distinguished 

 from similar species of the former. 



Subgenus 1. Tripodiscinus, Haeckel. 

 Definition. — Feet simple, not Ijranched nor forked. 



1. Tripodiscium tristylospyris, n. sp. 



Shell subspherical, with regular, circular pores, twice as broad as tlie bars. Mouth constricted, 

 half as broad as the shell, with three short spindle-shaped feet, which are nearly parallel and 

 vertical, lialf as long as the shell. (Similar to Tristylospyris scaphipcs, PI. 84, fig. 13, but without 

 sagittal rmg and constriction.) 



Dimensions. — Shell 0'08 long, 0'07 broad ; feet 004 long. 



Habitat. — Central Pacific, Station 265, depth 2900 fathoms. 



2. Tripodiscium ovatmn, n. sp. 



Shell ovate, rough, nearly as broad as long. Pores regular circular, double-contoured, twice 

 as broad as the bars. Mouth constricted, one-third as broad as the shell, with three convergent 

 short triangular feet. 



Dimrnsimis. — Shell O'l long, 009 broad ; feet 0'02 long. 



Habitat. — Central Pacific, Station 271, depth 2425 fathoms. 



3. Tripodiscium clavatum, n. sp. 



Shell ovate, smooth, one and a half times as long as broad. Pores irregular roundish, of 

 different sizes. Mouth constricted, two-thirds as broad as the shell, with three divergent, straight 

 club-shaped feet, nearly as long as the shell. 



Dimensions. — Shell 012 long, O'OS broad ; feet Ol long. 



Habitat. — Tropical Atlantic, Station 348, depth 2450 fathoms. 



' rry)odt«m(m= Shell mtli three .small feet ; Tf/a, TtMianK,). 



