EEPORT ON THE EADIOLARTA. 519 



thorny (with numerous smaller, and three to five larger spines) ; one very large conical terminal spine 

 on each pole of the main axis. 



Lime'tmons. — Eadius of the larger arm 0-3, of the smaller 0-15 ; distal breadth of the former 0-06. 

 of the latter 0-04 ; basal breath 0-02. 



Hahitat — South Atlantic, Station 333, surface. 



Genus 224. Aynphumenhnn,'^ Haeckel, 1881, Prodromiis, p. 460. 



Definition. — P o r o d i s c i d a with two simple, undivided, chambered arms, 

 opposite in one axis, connected hj a patagium. 



The genus Amphymenium diflfers from the preceding Amphihrachium, its ances- 

 tral form, by development of a patagium or connecticulum between both arms. This 

 forms a latticed or more spongy envelop, which surrounds either the middle part of 

 the shell, or the whole shell with exception of the distal ends of both arms. If the 

 envelop become very spongy, the shell may be confounded wdth the cylindrical 

 Ellipside Spongocore (nearly allied to Spongurus); possibly also Ommatogramma of 

 Ehrenberg belongs to this genus. 



Subgenus 1. Ommatogramma, Ehrenberg (?). 



Definition. — Both opposite arms of the same size and form, blunt, without terminal 

 spines. 



1. Amphymenium pupula, n. sp. (PI. 44, fig. 8). 



Both arms equal, twice as long as broad, three-jointed ; the terminal joint egg-shaped, as large 

 as both other joints together ; distal end rounded, blunt. Patagium nearly complete, enveloping 

 the arms with exception of the distal end. Perimeter nearly spindle-shaped. 



Dimcjisions. — Eadius of each arm 01 7, greatest breadth 0'06 ; transverse breadth of the 

 patagium 013. 



Hahitat. — Pacific, central area. Station 273, depth 2350 fathoms. 



2. Amphymenium, 7iaviculare, Haeckel. 



? Ommatogramma navicularis, Ehrenberg, 1872, Monatsber. d. k. preuss. Akad. d. 'Wiss. Berlin, 



p. 317 ; Abhandl. d. k. Akad. d. Wiss. Berlin, Taf. vi. fig. 7. 



Both arms ecj^ual, three times as long as broad, spongy, not jointed ; distal end a little cluli- 

 shaped, blunt. Patagium nearly complete, enveloping the arms with exception of the distal end. 

 Perimeter nearly lanceolate. The imperfect diagnosis and figure of Elireuberg make it doubtful 

 ' ylwip/!i/me(nHm = Shell with veil on both sides ; di^iDt, ii/.i,iiiov. 



