1160 THE VOYAGE OF H.M.S. CHALLENGER. 



3. Bathropyramis trapezoides, <n. sp. (PL 54, fig. 3). 



Shell smooth, broadly pyramidal, with four ortinar pores at the apex and eight (or sometimes 

 nine) stout radial beams, connected by twelve to sixteen complete octagonal horizontal rings. 

 Meshes trapezoidal, of nearly equal length, but gradually increasing in breadth. 



Dimensions. Shell 0'3 long, 03 broad. 



Habitat. Central Pacific, Station 265, depth 2900 fathoms. 



4. Bathropyramis interrupta, n. sp. (PI. 55, fig. 7). 



Shell smooth, flatly pyramidal, nearly discoidal, with four cortinar pores .at the apex and nine to 

 ten stout radial beams, connected by eight to sixteen interrupted rings ; the rings are complete only 

 in the apical part, in the distal part more or less irregularly interrupted. 



Dimensions. Shell 012 long, 0'36 broad. 



Habitat. North Atlantic, Station 354, surface. 



5. Bathropyramis medusa, n. sp. 



Shell smooth, flatly pyramidal, nearly discoidal, with four cortinar pores and numerous radial 

 beams (thirty to fifty) ; the four perradial of these are prolongations of the four cortinar beams, and 

 alternate with four interradial of the same size. Between these are intercalated eight adradial 

 beams arising from the third ring ; and between the former and the latter, sixteen to twenty-four 

 peripheral radial beams, arising from the fourth to the sixth ring. The inner four to six rings 

 are complete, the outer ten to fifteen irregularly interrupted. 



Dimensions. Shell 0'08 long, 0'3 to 0'4 broad. 



Habitat. South Atlantic, Station 338, surface. 



Subgenus 2. Cladopyramis, Haeckel, 1881, Prodromus, p. 428. 

 Definition. Shell spiny, with prominent simple or branched spines on the surface. 



6. Bathropyramis spinosa, n. sp. 



Shell spiny, slenderly pyramidal, with three cortinar pores at the apex and with nine strong 

 radial beams, connected by fifteen to twenty complete parallel rings. Meshes subregular square, 

 increasing gradually in size. Surface covered with simple, strong conical spines, arising from the 

 nodal points. 



Dimensions. Shell 0'24 long, 016 broad. 



Habitat. North Pacific, Station 244, depth 2900 fathoms. 



