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



8. Stauralastrum staurolonche, n. sp. 



Arms four times as long as broad at their base, gradually increasing towards their truncated 

 end, which is one and a half times as broad as their base ; their distal breadth equals the radius of 

 the central disk, which exlaibits four to five rings. At the end of each arm is a very strong 

 conical terminal spine. (Eesembles Histiastrum quaternarium, Abhandl. k. Akad. Wiss. Berlin, 1875, 

 Taf. xxiv. fig. 3, but has no patagium.) Edges of the arms rectilinear, divergent. 



Dimensions. — Eadius of each arm 0'25, basal breadth 0'045, distal breadth 0-07. 



JTahitat. — Fossil in the Barbados rocks ; and living in the depth of the Equatorial Atlantic, 

 Station 348, depth (2450) fathoms. 



9. Stauralastrum horridum, n. sp. 



Arms three times as long as broad at their base, gradually increasing towards their rounded 

 end, which is twice as broad as their base, their distal breadth equals the diameter of the central 

 disk, which exhibits four to five rings. Surface thorny, at the distal end of each arm is a group of 

 twenty to twenty-five smaller and five to six larger, straight, conical spines. Edges of the arms 

 rectilinear, divergent. 



Dime7isio)is. — Radius of each arm 015, basal breadth 0'05, distal breadth 01. 



Eabitat. — Pacific, central area, Station 270, depth 2925 fathoms. 



« 



Genus 234. Hagiastrum,^ Haeckel, 1881, Prodromus, p. 460. 



Definition. — P oro clis c i da with four simple, undivided, chambered arms, with- 

 out a patagium ; quadrangular shell bUateral, two opposite arms of the maia axis (or 

 principal arms) different from the two others (or lateral arms). 



The genus Hagiastrum, as here defined, was formerly united by me with the 

 foregoing Stauralastrum, but differs from it by the bilateral or symmetrical form. 

 Whilst in the latter all four arms and the four angles between them are equal, they are 

 here differentiated into pairs. 



Subgenus 1. Hagiastrella, Haeckel. 

 Definition. — Both longitudinal arms of equal size and form. 



1. Hagiastrum buddhae, n. sp. (PI. 45, fig. 5). 



Cross rectangular. Both longitudinal arms of equal size, twice as long as the transverse 

 arms ; aU arms smooth, club-shaped, twice as broad at their globose distal part as at their base, each 

 with three large conical terminal spines. 



1 Hagiastrum = Holy starrulet ; aytou, oSffT^oi/. 



