1036 THE VOYAGE OF H.M.S. CHALLENGER. 



Genus 445. Di2)OS2)yris,'^ Haeckel, 1881, Prodromus, p. 441. 



Definition. — Z y g o s p y r i d a with two simple free basal feet and one apical 

 horn. 



The genus Dipospyris and the following five genera represent together the interesting 

 subfamily of Dipos^jyrida, which always bear two opposite lateral feet only. Therefore 

 in this bipedal group the biradial or bilateral type of the S p y r o i d e a is particularh' 

 expressed. Such bipedal forms never occur in the Cyrtoidea. ■ The topographical 

 relation of the two lateral feet to the rods of the collar-plate, and to the cortinar pores 

 separated by these, leaves no doubt that they correspond to the pectoral feet of 

 Cortina and Tripospyris, and therefore that the Dipospyrida have originated from the 

 Tripospyrida by loss of the caudal foot. Diposp>yris is the simplest form of the Dipo- 

 spyrida, with two simple free feet. 



1. Dipospyris hipes, n. sp. ' 



Shell thorax-shaped, smooth, with deep sagittal stricture, two vaulted bosoms, and subregular 

 circular pores. Basal plate with two large collar pores only. Horn and feet equal, conical, straight, 

 about as long as the shell ; the feet widely divergent. 



Dimensions. — Shell 0'08 long, 012 broad ; horn and feet O^l to 015 long. 



Habitat. — Fossil in Barbados. 



2. Dipospyris 7nystax, Haeckel. 



Ceratosjjyris mystax, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlm, p. 66, Taf. xx. tig. 6. 



Shell elliptical spinulate, with slight collar stricture and large subregular circular pores. 

 Bas£!,l plate with three pores (?) Horn small conical, oblique, shorter than the shell. Feet 

 slender conical, longer than the shell, slightly curved, divergent. At the base of the columella, 

 between the two feet, a small rudiment of the last caudal foot is visible. 



Dimensions. — Shell 0"06 long, 0"1 broad ; horn 0'02, feet 012 long. 



Habitat. — ^Fossil in Barbados. 



3. Dipospyris cuhus, n. .sp. (PL 83, fig. 18). 



Shell box-shaped, subcubical, papillate, without external sagittal stricture, with numerous 

 subregular circular pores. Basal plate with three very large collar pores, surrounded by a circle of 

 smaller pores. Apical horn short and thick, scarcely half as long as the shell. Feet of the same, 

 form, longer than the shell, widely divergent. 



Dimensions. — Shell 0-08 long. Oil broad ; horn 0'03 long, feet 014 long. 



Habitat. — Central Pacific, Station 272, depth 2600 fathoms. 



' Dipospyris = 'Basket with two feet ; 3iVo:/5, airvni;. 



