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



composed of two to five confluent roundish pores. Surface a little thorny. The single polar 

 spine pyramidal, as broad at the base as one mesh, one-third as long as the axis. 



Dimensions. Major axis 012, minor axis 01 ; pores O'Ol to 0'02, bars 0'002 to 0006 ; length of 

 the single polar spine 0'03, basal thickness 0'02. 



Habitat. Central area of the Pacific, Station 270, depth 2925 fathoms. 



3. Lithapium monocyrtis, n. sp. (PI. 14, fig. 10). 



Proportion of the longer axis to the shorter = 7 : 6. Shell thick walled, with irregular, lobed 

 meshes, four to six on the half equator, three to six times as broad as the bars ; each mesh com- 

 posed of three to six confluent roundish pores. Surface quite smooth, without thorns. The single 

 polar spine pyramidal, as broad at the base as the largest mesh, half as long as the radius. (This 

 species is closely allied to the foregoing, but differs in the smooth surface and the larger meshes.) 



Dimensions. Major axis 015, minor axis 013; pores O'Ol to 0'03, bars 0'003 to O'Ol ;. length of 

 the single spine 0'04, basal thickness 0'03. 



Habitat. Central area of the Pacific, Station 268, depth 2900 fathoms. 



Genus 130. Pipettella, 1 n. gen. 



Definition. Ellipsida with simple ellipsoidal shell, the main axis of which is pro- 

 longed at the pole into two opposite hollow fenestrated tubes of equal size and similar form. 



The genus Pipettella is distinguished from the other Ellipsida by two hollow 

 perforated tubes, which are directed in the longer axis of the ellipsoidal shell and arise 

 from opposite poles of this axis. It may be derived from Cenellipsis by prolongation 

 of both poles of the main axis. As the same peculiar production of two opposite 

 latticed tubuli at the poles of the main axis obtains in nearly all families of 

 Prunoidea (Pipetta, Cannartus, Panarinm, Zygartus, Sec.), it may possess a 

 peculiar value in this group. 



1. Pipettella fusiformis, n. sp. 



Shell spindle-shaped, thin walled, the two opposite tubes being conical and not longer than the 

 short transverse axis of the ellipsoidal shell ; no sharp demarcation between them. The two axes 

 of the ellipsoid bear the proportion of 3:2. Network of the shell and of the tubes equal, delicate, 

 regular, hexagonal, with circular apertures of equal size ; fourteen to sixteen on the half equator of 

 the shell. Bars very thin. The shell of this species is similar to that of Cannartiscus amphi- 

 coniscus (PL 39, fig. 19), but possesses no equatorial stricture and no medullary shell. 



Dimensions. Longer axis of the ellipsoid 018, shorter axis 012 ; length of the tubes 01, their 

 basal breadth 0'05 ; pores of the network O'Ol, bars O'OOl. 



Habitat. Northern Pacific, Station 244, depth 2900 fathoms. 



1 Pipettella = Small pipette. 



