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



Species 1. Euplectella asi^evgillum, Owen. 



Someivhat curved tube, slightly widened towards the iqyper end, bearing external 

 ridges and cuff-like fringe. Circular parietal gaps alternate with closed meshes, and 

 are disposed in spiral rows, ascending at an angle of 4.5°. The principal supporting 

 spicules of the square-meshed framework are oxytetracts. The annular membrane round 

 the parietal gaps contains strongly developed compressed oxypentacts. Zebu (Philippines) ; 

 95 fathoms. 



Species 2. Euplectella suherea, Wyville Thomson. 



Straight, sonieivhat bulging tube, without ridges or cuff. Circular parietal gaps 

 alternate with closed arched meshes, and are spirally arranged, ascending at an angle of 

 45° The principal supporting spicules of the loosely united meshed framework are 

 strongly developed oxypentacts with distal radial ray. The annular memhrane of the 

 parietal gaps contains straight knotted diacts and sceptres. West of Gibraltar, 600 to 

 1090 fathoms ; north-east of Bahia, 1600 fathoms; off the Berlingues, 1600 fathoms. 



Species 3. Eupleetella cucumer, R. Owen. 



Straight, somewhat bulging tube, without ridges or cuff. Circular parietal gaps 

 alternate with closed arched projecting meshes, and are disposed in spiral rows, ascending 

 at an angle of 45°. The summit of each protruding arched mesh bears the projecting 

 distal ray of a strongly develop)ed oxyhexaster. Seychelle Islands. 



Species 4. Euplectella jovis, 0. Schmidt. 



Straight tube, somewhat widened towards the upper end, without external ridges, 

 but with a terminal marginal cuff. Round parietal gaps occur in approximately regular 

 .spiral rows. The principal supporting spicules of the square-meshed framework are 

 strongly developed oxypentacts, with long projecting distal ray. The annular mem- 

 brane of the parietal gaps contains sceptres and S-shaped clasps. Antille Islands, 42.3 

 fathoms. 



Species 5. Euplectella oweni, Marshall. 



Straight phallus-shaped tube, with oval cross section, without ridges or cuff. Cir- 

 cular parietal gaps arranged in longitudincd and transverse rows. The principal 

 supporting spicules of the square-meshed framework are strong oxytetracts. The annular 

 membrane of the parietal gaps contains compass-shaped oxydiacts disposed tangentially. 

 Japan. 



