1264 THE VOYAGE OF H.M.S. CHALLENGER. 



8. Acanthocorys macroceras, n. sp. (PI. 97, fig. 12). 



Cephalis large, hemispherical, spiny, with regular, circular pores, and a very large, cylindrical, 

 vertical horn five times as long as the whole shell. Thorax spiny, campanulate, with 

 irregular, roundish pores and nine strong, curved ribs, prolonged into nine slender, divergent feet 

 twice the length, which are curved, convex in the proxunal half and concave in the distal half. 



Dimensions. — Cephalis 0'05 long, 0'08 broad ; thorax 012 long, 0'2 broad. 



Habitat. — South Pacific, Station 298, depth 2225 fathoms. 



9. Acanthocorys furcata, n. sp. 



Cephalis large, subspherical, spiny, with irregular, roundish pores. Thorax flatly conical, thorny, 

 with irregialar, polygonal pores, decreasuig in size towards the mouth, and with nine straight 

 divergent riljs, which at the peristome are forked and prolonged into eighteen slender, very long, 

 bristle-shaped feet. 



Dimensions. — Cephalis 0'045 diameter, thorax 0"07 long, 0"13 broad. 



Habitat. — South Atlantic, Station 323, depth 1900 fathoms. 



Subgenus 3. Acanthocorythium, Haeckel. 



Definition. — Thorax with a variable number (ten to twenty or more) radial ribs, 

 prolonged into free terminal feet. 



10. Acanthocorys dodecaster, n. sp. 



CephaUs small, subspherical, with small circular pores and a large conical horn of twice the 

 length, and some accessory spines. Thorax thorny, flatly campanulate, with twelve stout curved ribs, 

 which at the peristome are prolonged into twelve slender, curved feet of twice the length ; four of 

 them are centrifugal prolongations of the four cortinar beams separating the four large meshes of the 

 collar septum ; eight other ribs are secondary, interpolated in pairs between the former. At the 

 base of the thorax are twelve large triangular holes between the riljs ; the other network is irregidar, 

 with polygonal meshes. 



Dimensions. — Cephalis 0'03 diameter, thorax 0"05 long, 012 broad. 



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



11. Acanthocorys polypodia, n. sp. 



Cephalis small, hemispherical, with small, roundish pores and divergent radial spines. Thorax 

 flatly conical, spiny, with twenty to twenty-four divergent, straight ribs, which in the proximal 



