1304 THE VOYAGE OF H.M.S. CHALLENGER. 



of about the same size, subcylindrical, smooth, truncate, with wide open mouth. Pores in both 

 joints of equal size, small, regular, circular. 



Dimensions. — Cephalis 0'04 long, 0-04 broad ; thorax 0'06 long, 0'05 broad. 



Habitat. — Cosmopolitan ; Atlantic, Indian, Pacific ; also fossil in Barbados. 



3. Lojjhojyhcena liothorax, ii. sp. 



Shell with distinct collar stricture. Length of the two joints = 4 : 10, breadth = 4 : 8. Cephalis 

 subglobular, with large, circular, hexagonally-framed pores, and with numerous stout, conical, radial 

 spines, about as long as its diameter. Thorax twice as long, ovate, smooth, truncate, with little con- 

 stricted mouth, and with irregular, roundish pores, of very different sizes. 



Dimensions. — Cephalis 0"04 long, 0"04 broad ; thorax O'l long, 0'08 broad. 



Ealitat. — Central Pacific, Stations 270 to 274, depth 2350 to 2925 fathoms. 



4. Loj^hophcena ecMnocephala, n. sp. 



Shell with deep collar stricture. Length of the two joints = 4:8, breadth = 4:9. Cephalis 

 subglobular, of the same shape as in the preceding species. Thorax thorny, inflate, nearly 

 spherical, with a constricted mouth of half the breadth, and with irregular, roundish, double- 

 contoured pores. 



Dimensions. — Cephalis 0^04 long, 0'04 broad ; thorax 0'08 long, 0'09 broad. 



Hahitat. — North Pacific, Station 253, depth 3125 fathoms. 



Subgenus 2. Lophopluenoma, Haeckel. 

 Definition. — Horns of the cephalis connected by anastomosing branches. 



5. Lopliophcena circumtexta, Haeckel. 



Loplioplixna radians, var., Ehrenberg, 1875, Abbandl. d. k. Akad. d. Wiss. Berlin, p. 78, 

 Taf. viii. figs. 7, 8. 



Shell with slight collar stricture. Length of the two joints = 4:5, breadth = 4:5. Cephalis 

 subglobular, with numerous conical, radial spines, about as long as its diameter, and at equal 

 distances from the surface, connected by anastomosing branches. Thorax nearly cylindrical, smooth, 

 little dilated towards the truncate, wide open mouth. Pores subregular, circular. 



Dimensions. — Cephalis 0'04 long, 0'04 broad ; thorax 0'05 long, 0'05 broad. 



Habitat. — Central Pacific, Stations 265 to 268, depth 2700 to 2900 fathoms ; also fossil in 

 Barbados. 



