410 



THE VOYAGE OF H.M.S. CHALLENGER. 



J. Phcronema — continued. 



No connected circlet of pleuralia below the oscular 

 border, but somewhat uniformly distributed tufts of 

 pleuralia, ...... 



3 Body resembling a chaffinch's nest, forming about two- 

 thirds of a sphere, with very long basal tufts. 



On the external surface of the body, which occupies 

 three-fourths of a sphere, there is both below the 

 oscular border and above the basis an annular 

 constriction, so that the whole has a bird's-nest form. 



The body, which occupies three-fourths of a sphere, has 

 no oscular constriction, and is superiorly somewhat 

 flattened, ...... 



VL Poliopogon, Wyv. Thomson. 



The body forms an ear-shaped plate. The parenchyma 

 contains no smooth oxydiacts, but only .sjsinose 

 uncinates, ...... 



PAGE AND PLATB 



Pheronema (lirjanteum, . 250 



XLV., XLVI. 



Phevonema grayi, 



246 



Pheronema hemisphmcum, 246 



Pheromma globosum, . 248 



xuv. 



Poliopogon amadou, 



254 



The body forms a very thick-walled, approximately 

 spherical goblet. The parenchyma includes small 

 spindle-shaped smooth oxydiacts, . 



VII. The skeleton either consists exclusively of isolated 



spicules, or exhibits synapticula and ladder-like 

 connections, resulting in an irregular secondary 

 union of various large spicules into a connected 

 compact framework (Lyssacina, Zittel, p.p. ; Hexas- 

 terophora, F. E. S.), 



Besides the isolated spicules there is an early and regular 

 fusion of uniform hexacts, independent of synap- 

 ticula, and forming a compact connected framework, 

 with no ladder-like structures (Dictyonina, Zittel), 

 VIII. Hexasterophoha, F. E. S. 



The dermal skeleton contains hypodermal dagger-shaped 

 hexacts (EdplectelliDjE), .... 



The autodermalia and autogastraUa are pentact or hexact 

 pinuli, in which the parenchymal radial ray is 

 altogether wanting or only weakly developed 



(ASCONEMATID^), ..... 



The autodermalia have no distal radial ray (Rossellid-e), 



IX. EUPLBCTELLID^. 



Tubular forms, with terminal sieve-plate and lateral 

 circular parietal pores. On the distal radial ray of 

 the dagger-shaped he.xact hypodermalia a floricome 

 is seated (Edplectellinjl), 



Tubular forms without lateral parietal apertures, and 

 without external floricomes (Holascin.e.), . 



Poliopogon giyan, . 257 



XX VII., XLVIII. 



VIII. 



XLIX. 



IX. 



XIX. 

 XXX. 



X. 

 XIII. 



