388 THE VOYAGE Of H.M.S. CHALLENGER. 



somewhat sharp-edged oscidar margin bears a wreath of pointed spicules. Numerous 

 tufts of radially disposed spicules project from the lateral surface of the body. The basal 

 tuft is formed of numerous separate tufts of spicules, which are interlaced at the outer 

 ends. In the external skin a thick network with irregular stellate structures is recognis- 

 able. The parenchyma contains, besides medium-sized uncinates, very numerous smaller 

 fomis with curved lateral spines. The large amphidiscs have a rather thick axial rod 

 and hemisphcrically arched terminal umbels wit\\ eight broad paddle-shaped rays. The 

 dermal pinuli have four rough, substantial, somewhat downward bent liasal rays, and a 

 moderately long l)usliy radial. Near Little Ki Island, 140 fathoms. 



Species 6. Phcronema giganteum, n. sp. 



An ellipsoidal body as big as a man's head, with a round oscular opening measuring 

 a hand's breadth across, and surrounded by cuff-like wreath of spicules. The smooth 

 external surface bears small scattered tubercle-like elevations, from the apex of each of 

 which a tuft of long radial pleuralia projects. These increase in length towards the lower 

 end, and measure more than a hand's length in the root-tuft at the base. The paren- 

 chyma includes, besides strong oxypentacts probably originating from the dermal skeleton, 

 small spinous oxyhexacts and uncinates of various length and with short barbs. The 

 large amphidiscs have a slender axial rod and hemispherical umbels with eight narrow 

 rays. The dermal pinuli have rough basal rays of medium length, and a somewhat long- 

 uniformly broad tufted radial. Near Little Ki Island, 140 fathoms. 



Genus 3. Polio2)ogon, Wyville Thomson. 



The body forms either a plump goblet or a thin ear-shaped involute plate. The 

 low^er end forms a broad basal tuft, while the upper bears a delicate fringe of spicules 

 round the sharp-edged oscular margin. The smooth external lateral surface hears 

 no pleural prostalia. The parenchyma includes, besides rough or spinose small 

 oxyhexacts, uncinates, and in one species also small smooth oxydiacts in variable al>un(l- 

 ance and size. The two anchor teeth of the basalia stand approximately at right angles 

 to the long almost smooth shaft. The marginalia are externally club-shaped. 



Species 1. Poliopogon amadou, Wyville Thomson. 



An ear-shaped semi-involute thick plate with sharpened oscular margin, bearing a 

 short and slender fringe of spicules. A fine square-meshed latticework is borne both on 

 the convex outer dermal, and concave inner gastral surface. The parenchyma contains 

 spinose oxyhexacts and numerous medium-sized uncinates. The larger amphidiscs have 



