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



siitural meshes. Eadial spines in the outer half fusiform, somewhat longer than the inner 

 cylindrical half. 



Dimensions. — Diameter of the shell 0'08 to 0-09, of the parmal meshes O'l to 0"2, of the 

 sutiiral meshes 0-004 to O'Ol. 



Habitat. — Central Pacific, Station 271, surface. 



2. Dorataspis macracantha, n. sp. 



Shell with fifty-two sutures and fifty-two sutural meshes ; with four hexagonal and sixteen 

 pentagonal jjlates. Both aspinal meshes of each plate circular, small, twice as broad as the small 

 sutural meshes. Eadial spines quadrangular, prismatic, their outer half twice to three times as 

 long as the inner half. 



Dimensions. — Diameter of the shell 0'12, of the parmal pores O'OOS, of the sutural meshes 

 0-004. 



Habitat. — South Pacific, Station 288, surface. 



3. Dorataspis macrop>oya, n. sp. 



Shell with fifty-two sutures and one hunrlred to one hundred and fifty sutural meshes, with 

 four hexagonal and sixteen pentagonal plates. Both aspinal meshes nearly circular, very large, five 

 to ten times as broad as the small circular sutural meshes ; the number of the latter is in this 

 species multiplied, in each suture being two to three (commonly three) small pores. Eadial spines 

 in the outer half leaf-shaped, compressed, nearly lanceolate, longer than in the inner cylinch-ical 

 half. 



Dimensions. — Diameter of the shell 0-16, of the parmal pores 0-03 to 0-04, of the sutural pores 

 0-004 to 0-006. 



Habitat. — Indian Ocean (Madagascar), Eabbe, surface. 



Subgenus 2. Dorataspidium, Haeckel. 



Definition. — Shell with fifty -four sutures ; four polar plates on each pole of the 

 main axis different in pairs ; t-v\^o major hexagonal meeting in a ^jolar suture (the 

 " hydro tomical suture ") ; t-^'o minor pentagonal, not meeting together (separated by 

 that hydrotomical suture). Spherical shell therefore composed of eight hexagonal 

 plates (four equatorial and four polar) and by twelve pentagonal plates (eight tropical 

 and four polar plates). 



4. Dorataspis loricata, Haeckel. 



Dorataspis loricata, Haeckel, 1862, Monogr. d. Eadiol., p. 415, Taf. xxi. figs. 3-6. 



Shell with fifty-four sutures aird fifty-four sutural meshes, with eight hexagonal and twelve 

 pentagonal plates. Both aspinal meshes of each plate kidney-shaped or roundish, nearly of the 



