1462 THE VOYAGE OF H.M.S. CHALLENGER. 



Dimensions. Length of the shell (with four joints) O2, breadth, O08. Length of the single 

 joints, a 0'02, I 0"03, c 0'03, d 012. 



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



7. Cyrtophormis corona, ru sp. (PL 77, fig. 15). 



Shell smooth, conical, ovate, with three deep strictures, about twice as long as broad. The 

 fourth joint is the broadest, inflated, and three times as long as the second and the third joints. 

 Pores small and numerous, circular, in regular, transverse rows ; two in the first joint, four in the 

 second and third, and ten in the fourth joint. Cephalis hemispherical, with a stout, pyramidal horn. 

 Peristome two-thirds as broad as the fourth joint, with twelve to fifteen triangular, convergent teeth. 



Dimensions. Length of the shell (with four joints) 016, breadth 0'08. Length of the single 

 joints, a O'Ol, b 0'03, c 0'03, d 0'09. 



Habitat. Western Tropical Pacific, Station 225, depth 4475 fathoms. 



8. Cyrtophormis cornuta, n. sp. (PL 77, fig. 18). 



Shell thorny, spindle-shaped, with three distinct strictures. Length of the four joints = 

 2:4:3:5. The third joint is the broadest. Pores circular, of different sizes, in the three first 

 joints double-contoured. Cephalis subspherical, with a large, conical horn of three times the 

 length. The fourth joint is inversely conical, three times as broad as the constricted mouth. 

 Peristome with a coronal of numerous (ten to twenty) irregular, thin, partly forked teeth. 



Dimensions. Length of the shell (with four joints) 014, breadth 0'07. Length of the single 

 joints, a 0'02, b 0'04, c 0'03, d 0'05. 



Habitat. Central Pacific, Station 265, depth 2900 fathoms. 



9. Cyrtophormis Jimbriata, Haeckel. 



Lithocampe fimbriata, Stohr, 1880, Pataeontogr., vol. xxvi. p. 103, pi. iv. fig. 3. 



Shell rough, spindle-shaped, with six annular septa. The fifth joint is the longest, twice as 

 long as each of the three preceding joints, and four times as long as the sixth. The fourth joint is 

 the broadest, three times as broad as the constricted mouth. Pores small, regular, circular. 

 Cephalis small, subspherical, with a small, conical horn (broken off in the specimen figured). 

 Peristome with an irregular, double coronal of ten to twenty vertical teeth. 



Dimensions. Length of the shell (with seven joints) 0'25, breadth 01. Length of the fifth 

 joint 0'06, of each of the three preceding 0~03. 



Habitat. Central Pacific, Station 268, depth 2900 fathoms ; fossil in Sicily (Grotte, Caltanisetta). 



10. Cyrtophormis turrita, n. sp. 



Shell smooth, nearly conical, twice as long as broad, with twelve sharp strictures. The thirteen 

 joints increase gradually in length and breadth. The last joint is much longer than any of 



