1484 THE VOYAGE OF H.M.S. CHALLENGER. 



2. Lithomitra acephala, Biitschli. 



Lithomitra acephala, Biitschli, 1882, Zeitschr. f. wi?s. Zool., vol. xxxvi. p, 529. 



Eucyrtidium acepfialum, Ehienberg, 1875, AbhandL d. k. Akad. d. Wiss. Berlin, p. 70, Taf. 



xi. fig. 5. 

 Eucyrtidium obstipum, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 70, Taf. xi. 



fig. 17. 



Shell nearly cylindrical, smooth, thick-walled, with twelve to sixteen subequal joints. On each 

 joint a single row of small circular pores. No external strictures. Scarcely differing from the pre- 

 ceding species ; the joints are broader and shorter, the cephalis is larger (by union of some joints 1), 

 and the ribs of the surface less distinct. 



Dimensions. Length of the shell (with .twelve joints) O'l ; length of each joint O'OOG to 0'009, 

 breadth 0'04. 



Habitat. Fossil in Barbados. 



3. Lithomitra lineata, HaeckeL 



Lithocampe lineata, Ehrenberg (partim), 1838, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, 



p. 130; Mikrogeol., 1854, Taf. xxii. fig. 26. 

 Lithocampe lineata, Haeckel, 1862, Monogr. d. Eadiol., p. 316. 

 Eucyrtidium lineatum, Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 43 ; 



Mikrogeol., 1854, Taf. xxxvi. fig. 16; Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 72, 



Taf. xi. fig. 9. 

 Dictyomitra lineata, Stb'hr, 1880, Palaeontogr., vol. xxvi. p. 101, Taf. iii. fig. 22. 



Shell subcylindrical, smooth, with longitudinal ribs, and four to eight slight transverse strictures. 

 Cephalis small, subspherical, with few small pores. Thorax broader, with two or three transverse 

 rows of pores. Each succeeding (abdominal) joint with a single transverse row of small pores. 

 Variable and nearly related to the two preceding species (compare my Monograph, loc. cit.~). 



Dimensions. Length of the shell (with six to eight joints) 0'06 to 0'08; length of each joint 

 (on an average) O'Ol, breadth 0'03. 



Habitat. Cosmopolitan ; Mediterranean, Atlantic, Indian, Pacific, in various depths; many 

 stations ; fossil in Secondary and Tertiary rocks of many places. 



4. Lithomitra nodosaria, n. sp. (PL 79, fig. 1). 



Shell subcylindrical, with longitudinal ribs, and five to eight transverse strictures, and promi- 

 nent girdles between them. On each girdle (at the lowermost edge of each joint) a single transverse 

 row of circular pores. The three or four uppermost joints are united, and represent a conical 

 cephalis. 



Dimensions. Length of the shell (with six joints) O'l; length of each joint O'Ol to 0'15, 

 breadth 0'04 to 0'05. 



Habitat. Central Pacific, Station 263 to 274, depth 2350 to 2925 fathoms. 



