1520 THE VOYAGE OF H.M.S. CHALLENGER. 



4. Artocapsa quadricamera, n. sp. 



Shell spindle-shaped, smooth, with three sharp strictures. Length of the four joints = 2:3:4:8. 

 The third joint is the broadest. The fourth joint is inversely conical, nearly as long as the three 

 other joints together, and bears a strong, conical, basal spine, of half the length. The cephalis is 

 small, subspherical, and bears a conical horn of the same length. Pores subregular, circular. 



Dimensions. — Length of the shell (with four joints) OlV, breadth 0-08. Length of the single 

 joints, a 0-02, h O'OS, c 0-04. d 0-08. 



Hahitat. — Fossil in Barbados. 



5. Artocapsa armata, n. sp. 



Shell slender, inversely ovate, spiny, with six deep strictures. Length of the seven joints = 

 2:4:6:5:4:3:2. The third joint is the broadest, inflated, and much larger than the four foUovv- 

 iuCT, which gradually decrease in size. The small, hemispherical cejihalis bears a stout pyramidal 

 horn of twice the length. The last hemispherical joint is armed with a bunch of stout spines, one 

 of which is much the larger, and as long as the third joint. Pores irregular, roundish. 



Dimensions. — Length of the shell (with seven jomts) 0-26, breadth 0-12. Length of the single 

 joints, a 0-02, h 0-04, c 0-06, cl 0-0.5, e 0-04,/ 0-03, g 0-02. 



Hahitat. — Western Tropical Pacific, Station 225, depth 4575 fathoms. 



6. Artocapsa octocamera, n. sp. 



Shell subcylindrical, smooth, with seven internal annular septa. Five joints (the third to the 

 seventh) are nearly equal in size, whQe the second and eighth are cupola-shaped, somewhat longer. 

 The cephalis is smaller, with a conical horn of the same length. The last joint bears a bunch of 

 divergent, conical spines, of different lengths. Pores small, regular, circular. 



Dimensions. — Length of the shell (with eight joints) 016, breadth O'OS. Length of the cephalis 

 0-016, second and eighth joints 0033, each of the five other joints 0-022. 



Eabitat. — South Pacific, Station 285, depth 2375 fathoms. 



7. Artocapsa elegans, n. sp. (PI. 76, fig. 8). 



Shell spindle-shaped, smooth, with eight internal, broad, annular septa. The second and third 

 jomts are the largest, the fourth and fifth of medium size, while the cephalis and the four last joints 

 are nearly equal in length, and much shorter. The third joint is the largest. The subspherical cephalis 

 bears a bristle-shaped horn of the same length, while the last joint is armed with a bunch of conical 

 spines. Pores small, in the upper half of the shell regular, hexagonal, in the lower half irregular. 



Dimensions. — Length of the shell (with nine joints) 0-2, breadth 0-09. Length of the first and 

 the four last joints, each 0-014 ; of the fourth and fifth, each 0-02 ; of the third 0-04, second 005. 



Habitat. — Central Pacific, Station 274, depth 2750 fathoms. 



