1376 THE VOYAGE OF H.M.S. CHALLENGER. 



circular, half as broad in the cephalis as in the two other joints. Thorax cauipanulate. Abdomen 

 truncate, with eighteen to twenty-four parallel, vertical, longitudinal ribs, which are prolonged into 

 slender, free, conical feet of the same length. (This remarkable species may be derived from 

 Carpocanium by apposition of a third joint.) 



Dimensions. Length of the three joints, a 0'03, b 0'05, c 0'04 ; breadth, a 0'03, b 006, c 0'05. 



Habitat. Fossil in Barbados. 



Genus 604. Cycladophora, 1 Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. 



d. Wiss. Berlin, p. 54. 



Definition. T heophormida (vel Tricyrtida multiradiata aperta) with four to 

 six or more radial ribs in the abdomen, the terminal mouth of which is truncate, with- 

 out feet. 



The genus Cycladophora differs from the preceding Alacorys, its probable ancestral 

 genus, in the absence of free terminal feet, the radial ribs of the abdomen being con- 

 nected by transverse beams throughout their whole length. The number of the 

 regularly disposed ribs (four to six or more) may also here be used for the distinction of 

 different subgeuera. 



Subgenus 1. Lampterium, Haeckel, 1881, Prodromus, p. 434. 



Definition. Abdomen with four radial ribs, opposite in pairs in two meridian 

 planes, perpendicular one to another. 



1. Cycladophora gcetheana, n. sp. (PI. 65, fig. 5). 



Shell shaped like a lantern, with two sharp strictures. Length of the three joints = 1:2:12, 

 breadth = 1:4:7. Cephalis hemispherical, with a slender pyramidal horn of three times the length. 

 Thorax twice as large, thorny, hemispherical, with regular, circular pores. Abdomen very long, 

 nearly four-sided prismatic, with four superior smaller, and four inferior larger holes ; the former 

 separated by four short, divergent, perradial, the latter by four long, parallel, vertical, interradial 

 bars. Mouth square, four-lobed. Dedicated to Wolfgang Goethe. 



Dimensions. Length of the three joints, a 0'02, b 0'04, c 0'24 ; breadth, a 0'03, b 0'07, c 01 to 

 014. 



Habitat. Central Pacific, Stations 265 to 269, depth 2550 to 2900 fathoms. 



2. Cycladophora tetrapleura, n. sp. 



Shell very similar to the preceding species, but differing in the following characters : Cephalis 

 conical, with a horn of the same length. Thorax campanulate. Four ribs of the abdomen not 



1 Cycladophora = Bearing a female robe ; xt/xXa 



