1142 THE VOYAGE OF H.M.S. CHALLENGER. 



fissure. The apex beai's a short and stout, three-sided pyramidal horn, the hollow base of which is 

 closed by a small cortinar septum with three collar pores (fig. 8h). This seems to indicate a 

 rudimentary cephalis and the derivation of this species from Lijchnocanium (PL 61). Peristome 

 constricted, only one-fourth as broad as the shell, with three short, conical, nearly vertical feet. 

 The central capsule (fig. 8a) in the specimen examined was well preserved, hemispherical, not lobate, 

 and filled up the upper half of the shell-cavity (beyond the rudiment of the cortinar septum). 



Dimensions. — SheU 0'2 long, 0"12 broad ; horn O'Ol long, feet 0'fl2 long. 



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



7. Tripilidium donyatum, n. sp. 



SheU elongate, smooth, nearly cylindrical, in the upper third conical. Pores small and 

 numerous, regular, circular, half as broad as the bars, disposed in alrout thirty longitudinal alternatmg 

 rows. Peristome scarcely constricted. The apical horn and the three parallel feet are of equal size 

 and similar form, straight, conical, one-sixth as long as the shell. 



Dimensions. — Shell 0'12 long, 0"06 broad ; horn and feet 002 long. 



Habitat. — Fossil in Barbados. 



Subgenus 2. Tripodocorys, Haeckel, 1881, Prodromus, p. 428. 

 Definition. — Feet forked or branched. 



8. Tripilidium dichopodium, n. sp. 



Shell hemispherical, nearly twice as broad as long, smooth. Pores irregular, roundisli, twice to 

 four times as broad as the bars. Mouth wide open. Apical horn spindle-shaped, half as long as 

 the shell. Three feet cylindrical, nearly straight and parallel, as long as the shell, forked at the 

 distal end. (Exhibits an external similarity to Triposjjyris scmantis, PI. 84, fig. 2, but has no trace 

 of sagittal ring and constriction, and the simple shell-cavity has a wide open mouth.) 



Dimensions. — 0'06 long, 01 broad ; horn 0"03 long, feet 0'07 long. 



Habitat. — North Pacific, Station 241, depth 2300 fathoms. 



9. Tripilidinm cladoptodium, n. s]:). 



SheU campauulate, rough, about as long as broad. I'ores subregular, circular, as broad as tlie 

 bars. Mouth slightly constricted. Apical horn and three divergent feet of nearly equal size and 

 form, three-sided prismatic, straight and stout, irregularly dentate and bi'anched, somewhat longer 

 than the shell. 



Dimensions. — Shell O'OS diameter; horn and feet 0"1 to 012 long. 



Habitat. — Central Pacific, Station 205, deptli 2900 fathoms. 



