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



one mesh ; one of the spines longer than the shell diameter, the opposite spine nearly as long as 

 the shell radius ; both lateral spines scarcely one-third as long. 



Dimensions. Diameter of the shell 01, pores O'Ol, bars 0'005 ; length of the major spine 

 014, of the opposite 0'04, of both lateral spines 0'012. 



Habitat. Central Pacific, Station 266, depth 2750 fathoms. 



2. Stylostaurus gladiatus, n. sp. 



Shell thick walled, smooth, with regular, circular pores, three times as broad as the bars ; 

 nine to ten on the quadrant. Spines three-sided prismatic, as broad at the base as one mesh ; 

 one of the spines longer than the shell diameter, and much larger than the other three, which are 

 nearly equal (half as long as the radius). 



Dimensions. Diameter of the shell 0'2, pores 0'015, bars 0'005 ; length of the major spine - 25, 

 of the three others 0'005. 



Habitat. Central Pacific, Station 271, depth 2425 fathoms. 



Subfamily STAUROLONCHIDA, 1 Haeckel, 1881, Prodromus, pp. 449, 451. 

 Definition. S taurosphserida with two concentric spherical lattice-shells. 



Genus 63. Staurolonche,'' Haeckel, 1881, Prodromus, p. 451. 



Definition. S taurosphserida with two concentric lattice-spheres and four 

 crossed, equal, simple spines. 



The genus Staurolonche may be derived either from Staurosphcera by the duplication 

 of the lattice-sphere, or from Carposphcera by the production of four crossed radial 

 spines, lying in one meridional plane, or from Hexalonche by the reduction of two opposite 

 spines. 



Subgenus 1. Staurolonchantha, Haeckel. 



Definition. Pores of the cortical shell regular, and of nearly equal size and similar 

 form ; surface smooth. 



1. Staurolonche hexagona, n. sp. 



Haliomma hexagonum, Ehrenberg, 1854, Mikrogeol., Taf. xxxvb., Bd. iv. fig. 17. 

 Haliomma hexugonum, Haeckel, 1862, Mouogr. d. Radio!., p. 434. 



Cortical shell thin walled, smooth, three times as broad as the medullary shell, with regular, 

 hexagonal pores, four times as broad as the bars ; seven to eight on the quadrant. Tour spines three- 

 sided pyramidal, somewhat longer than the radius, as broad at the base as one mesh. 



1 Staurolonchida = Staurospha3rida duplicia = Dyosphserida tetracantha. 



2 Staurolonche = Crossed spear ; arctv^o 



