300 THE VOYAGE OF H.M.S. CHALLENGEE. 



3. Ellipsostijlus psittacus, n. sp. (PI. 13, fi^'. G). 



Proportion of the major axis to the minor = 4:3. Shell thin walled, with regular or subregular 

 rosette-shaped meshes, twice as broad as the bars ; eight to nine on the half equator ; each mesh 

 with three to four rounded lobes. Surface smooth. Polar spines sharp edged, very unequal ; 

 longer spine about twice as long as the major axis, somewhat curved ; shorter spine scarcely longer 

 than the radius, shaped like a bird's head. 



Dimensions. — Longer axis 0'08, shorter axis 0"06 ; pores O'Ol, bars 0-005 ; length of the polar 

 spines — ^longer 015, shorter 005. 



Habitat. — Central area of the Pacific, Station 266, depth 2750 fathoms. 



4. EUipsostylus aqnila, n. .sp. (PI. 13, fig. 1). 



Proportion of the major axis to the minor = 7 : 6. Shell thick walled, with subregular, circular 

 meshes, five to six times as broad as the bars ; ten to twelve on the half equator. Surface smooth. 

 Polar spines sharp edged (six-sided ?), very unequal ; longer spine straight, about equal to the mmor 

 axis ; shorter spine obliquely inserted, scarcely half as long, shaped like a bird's head. 



Dimensions. — Longer axis 015, shorter axis 013; pores 0-02, bars 0-004; length of the polar 

 spmes — longer O'l, shorter 005. 



Habitat. — Central area of the Pacific, Station 272, de]ith 2GO0 fatlioms. 



5. EUipsostylus columba, n. sp. (PL 13, fig. 3). 



Proportion of the major axis to the minor = 4:3. Shell egg-shaped, thin walled, with regular, 

 circular meshes, three times as broad as the bars ; ten to twelve on the half equator. Surface 

 somewhat thorny. Polar spines nearly of equal length (equal to the major axis), but of very 

 different form ; one straight, pyramidal, and obliquely inserted, the other like a bird's head. 



Dimensions. — Longer axis 0-08, shorter 0-06 ; pores 0-00:'., bars 0-01 ; length of the spines 0-09. 



Habitat. — South Atlantic, Station 332, surface. 



6. EUipsostylus ciconia, n. sp. (PL 13, fig. 8). 



Proportion of the major axis to the minor = 7:5. Shell egg-shaped, thick walled ; the meshes 

 very small, regular, circular, three times as broad as the bars ; sixteen to twenty on the half equator. 

 Surface uneven. Polar spines nearly cylindrical, pointed ; the smaller obliquely inserted, equal to 

 the major axis ; the larger more than twice as long and thick, furrowed at its base. (Compare with 

 this and the allied species Bhabdolithis pipa, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. P>erlin, 

 T;if. i. fig. 27.) 



}?f Dimensions. — Longer axis 0-07, shorter 0'05 ; pores 0-003, bars 0-001 ; length of the polar 

 spines — longer 0-2, shorter 0-08. 



Habitat. — North Pacific, Station 253, depth 3125 fathoms. 



