1612 THE VOYAGE OF H.M.S. CHALLENGEE. 



Subfamily 2. Sagmarida, Haeckel. 



Definition. — Sago sph re rid a with a spongy spherical shell, the thickened wall 

 of which is composed of a loose spongy framework. 



Genus 679. Sagmarium, n. gen. 



Definition. — S agosphasrida with a spongy spherical shell, the thickened wall 

 of which is composed of a loose spongy framework, and exhibits a smooth surface, 

 without radial spines and pyramidal elevations. 



The genus Sagmaritmi, and the following two genera of Sagosphaerida, represent 

 together the subfamily Sagmarida, differing from the preceding Sagenida in the spongy 

 structure of the shell-wall. Whilst in the latter the thin wall of the delicate spherical 

 shell is composed of a simple lattice-plate with triangular meshes, in the former numerous 

 liranches diverge from the nodal points of these meshes, and produce by union an 

 irregular and loose spongy framework. The surface of this spongy hollow sphere 

 (similar to Plegmot!j)ha3ra) is in Sagmarium smooth. 



1. Sagmarium spongodicti/um, n. sp. (PI. 108, fig. 2). 



Spongy wall of the hollow sphere about half as thick as the radius of its cavity. Bars of the 

 spongy framework veiy tliiu and fragile, smooth, without thorns. 



Dimensions. — Diameter of the sphere 2'0 to 24; length of the bars 01 to 0"2, breadth O'OOl. 

 Hahitat. — South Atlantic, Station 333, surface. 



2. Sagmarium plegmosphcerium, n. sp. (PL 108, fig. 14). 



Spongy wall of the hollow sphere about one-fourth as thick as the radius of its cavity. Bars 

 of the spongy framework rather stout, studded with numerous small spines, which arise perpen- 

 dicularly from their surface. 



Dimensions. — Diameter of the sphere 1'2 to 1'5, length of the bars 01 to 016, breadth 0'004. 



Hahitat. — Tropical Atlantic, Station 347, surface. 



3. Sagmarium trigonizo7i, Haeckel. 



Didyosoma trigonizon, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 841. 

 Spongodietyon trigonizon, Haeckel, 1862, Monogr. d. Eadiol., p. 459, Taf. xxvi. figs. 4, 5. 



Bars of the spongy framework thin, hregularly curved, bearing scattered small crosses, which 

 are composed of four small rods arising perpendicularly from the bars. Nodal points of the frame- 



' Sagmarium = Covering of a shield, armour ; aayfia^iou. 



