REPORT ON THE RADIOL ARIA. 145 



half equator. Irregulaiiy scattered betweeu them short conical thorns. Polar spines conical, 

 about as long as the axis of the outer sheU, as broad at the base as the inner shell. 



Dimensions. — Diameter of the outer shell 0-2, middle shell O'OG, inner shell 0-04; pores of the 

 cortical shell 0-005 to 0-02, bars 0-006 ; length of the polar spines 0-17, basal breadth 0-04 



Habitat. — North Atlantic, Gulf Stream, near Florida, depth 1500 fathoms, Schaffner. 



Genus 52. Amphistylus,^ Haeckel, 1881, Prodromus, p. 452. 



Definition. — S t y 1 o s p li fe r i d a with three concentric lattice-spheres and two free 

 spines of different size or form. 



The genus Amphistylus differs from its ancestral form, AmphisphcBra, by the 

 differentiation of both polar spines, and exhibits therefore the same rehation to it that 

 Sphcerostylus bears to StylospluBra. 



1. Amphistylus clio, n. sp. 



Eadial proportion of the three spheres = 4 : 2 : 1. Cortical shell tliick walled, smooth ; its pores 

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

 Polar spines three-sided pjTamidal, very stout, as broad at the base as the inner medullary shell ; 

 major spine somewhat longer than the diameter of the cortical shell ; minor spine scarcely half as 

 long. (Similar to Stylosphxra clio, PI. 16, fig. 7, but different iu the double medullary shell and 

 the different length of the polar spines.) 



Dimensions. — Diameter of the outer sphere 0-15, middle 0-08, inner 0-04 ; pores of the outer 

 .shell 0-01, bars 0-003 ; length of the major spine 0-17, minor 0-07, basal breadth 0-04. 



Habitat. — ^Pacific, central area. Station 265, depth 2900 fathoms. 



2. Amphistylus hippoGampus, n. sp. 



Eadial proportion of the three spheres = 3 : 2 : 1. Cortical shell thick walled, smooth ; its pores 

 regular, circular, hexagonally lobed, three times as broad as the bars ; twelve to fifteen on the half 

 equator. Major polar spine tliree-sided pja-amidal, about as long as the axis of cortical shell ; 

 minor spine pommel-like, edged, scarcely one-third as long. (Similar to Sphcerostylus hippocampus, 

 PI. 16, figs. 10, 11, but differs in the larger size, the double medullary shell, and the straight, not 

 curved, major spine.) 



Dimensions. — Diameter of the outer sphere 0-11, middle 0-07, inner 0-035; pores of the outer 

 shell 0-011, bars 0-004; length of the major sjiine 0-12, of the minor 0-04, breadth 0-03. 



Habited. — North Pacific, Station 244, depth 2900 fathoms. 



3. Amphistylus glyptodon, n. sp. 



Ptadial proportion of the three spheres = 6:3:1. Cortical shell thick waUed, spiny, with 

 irregular, roundish pores, two to four times as broad as the bars ; ten to twelve on the half equator. 

 ^ Amphistylus ^Sh^W with styles on both poles ; «,«?/, arvM;. 



(ZOOL. CHALL. EXP.— PART XL. 1885.) Ef 19 



