REPORT ON THE RADIOLARIA. 1143 



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



Definition. A rchipilida (vel Monocyrtida triradiata aperta) without lateral 

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



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

 loss of the apical horn, or from .the nearly related Tristylospyris 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 branched nor forked. 



1. Tripodiscium tristylospyris, n. sp. 



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

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

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

 sagittal ring and constriction.) 



Ditnensions. Shell O08 long, O07 broad ; feet 0'04 long. 



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



2. Tripodiscium ovatum, u. 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. 



Dimensions. Shell 01 long, 0'09 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, 0'08 broad ; feet 01 long. 



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



1 Tripodiicium= Shell with three small feet ; TJI, weB<Vio. 



