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



Dimensions. — Main axes of the four shells — (A) iunermost 0'035, (B) second O'OS, (C) third 

 015, (D) outermost 0-2 ; their equatorial axes — (A) O'OS, (B) O'OS, (C) 012, (D) 016 ; pores 

 0-004 to 0-016, bars 0-002 to 0-004. 



Habitat. — Western Tropical Pacific, Station 198, depth 2150 fathoms. 



Subgenus 2. Ca7-yodruppula, Haeckel. 



Definition. — Shell composed of five or more concentric shells (two medullary and 

 three or more cortical). 



2. Cromyodruppa mango, n. sp. 



Shell composed of six ellipsoidal, concentric shells, two medullary and four cortical. Pro- 

 portion of tlieir main axes = 2 : 3 : 8 : 11 : 14 : 18. Network of the two medullary shells and of 

 the innermost cortical shell subregular, with subcircular pores, about the same breadth as the bars. 

 Network of the three outer cortical shells more lax, with larger, irregular, roundish pores, twice to six 

 times as broad as the bars. The size of the pores and bars increases gradually from the innermost 

 to the outermost shell. Surface smooth. 



Dimensions.- — Main axis of the six shells— (A) innermost 004, (B) 0-06, (C) 0-16, (D) 0-22 

 (E) 0-28, (F) 0-35; their equatorial axes — (A) innermost 0-03, (B) 0-05, (C) 0-12, (D) 0-16, 

 (E) 0-2 ; (F) 0-25 ; pores 0-003 to 0-02, bars O'OOS to 0-005. 



Hahitat. — Indian Ocean, surface ; Matura, Ceylon, Haeckel. 



Genus 136. Cromyocarpus,^ n. gen. 



Definition. — Druppulida with four or more concentric shells (two medullary 

 'and two or more cortical shells), with numerous radial spines, but without polar tubes. 



The genus Cromyocarpus differs from Cvomyodruppa only in the development of 

 numerous large radial spines which start from the outer surface of the shell. It 

 exhibits therefore the same relation to the latter that Prunocarpus bears to Prunulum, 

 or Drup2D0carp>us to Druppida. It differs from both in the multiplication of the 

 cortical sheU. 



1. Cromyocarpus quadrifarius, n. sp. 



Shell composed of four concentric shells, two ellipsoidal cortical shells, and two spherical 

 medullary .shells. Proportion of their main axes = 10 : 8 : 3 : 2. Pores of the two cortical shells 

 irregular, roundish, twice to foiu- times as broad as the bars. Pores of the two medullary shells 

 subi-egular, . circular, about the same size as the bars. Outer surface covered with numerous 

 conical radial spines, aljout half as long as the main axis, half as broad at the base as the inner- 

 most shell. 



1 Cromyocarpus = Oiaon. fi'uit ; xqoiyLvon, xajTro?. 



