1482 THE VOYAGE OF H.M.S. CHALLENGER. 



2. Artostrobus elegans, Haeckel. 



? Eucyrtidium elegans, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 70, 



pL xi. fig. 12. 

 ? Eucyrtidium pauperum, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 72, 



pi. xi. fig. 13. 



Shell cylindrical, smooth, with eight to ten internal annular septa. Cephalis subspherical, 

 with a short, conical horn. Thorax campanulate, with two transverse rows of pores. Abdomen 

 with six to eight equal joints, each with a single row of pores. (May be described, perhaps, better 

 as Theoeyrtis elegans. Eucyrtidium pauperum, Ehrenberg, loc. tit., may be a variety of this species.) 



Dimensions. Length of the shell (with nine joints) 01; length of each abdominal joint O'Ol, 

 breadth O03. 



Habitat. Fossil in Barbados. 



Subgenus 2. Artostrobium, Haeckel. 



Definition. All (or the majority) of the joints of the shell with several transverse 

 rows of pores, in variable number. 



3. Artostrobus auritus, Haeckel. 



Lithocampe aurita, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 84. 

 Lithocampe auricula, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 71. 

 Eucyrtidium auritum, Ehrenberg, 1854, MikrogeoL, Taf. xxii. fig. 25. 

 Eucyrtidium auritum, Stohr, 1880, Pakeontogr., vol. xxvi. p. 104, Taf. iv. fig. 7. 



Shell subcylindrical, with five sharp strictures. All six joints nearly equal in length ; each 

 with four or five transverse rows of small pores. Cephalis small, flat, hemispherical, with two or 

 three small, conical, oblique horns. Mouth of the sixth joint a little constricted. 



Dimensions. Length of the shell (with six joints) O12; length of each joint (on an average) 

 0-02, breadth 0'04 to 0'05. 



Habitat. Fossil in Tertiary rocks of Sicily (Grotte, Caltanisetta). 



4. Artostrobus biseriatus, n. sp. 



Shell cylindrical, smooth, with ten to twelve deep strictures. All joints nearly equal in 

 size ; each with two transverse rows of small circular pores. Cephalis hemispherical, with a long, 

 bristle-shaped, curved horn. 



Dimensions. Length of the shell (with twelve joints) 0'24 ; length of each joint 0'02, breadth 

 0-04. 



Habitat. Tropical Atlantic, Station 348, depth 2450 fathoms. 



