the ^Challenger ' Monaxonida. 477 



[Agelas maurtttanus, Carter. 

 Locality/. OfF Tristan d'Acunha ?] 



Genus Echinodictyum * (Ridlej). 



Skeleton reticulate, with little spongin. Skeleton-spicules 

 smooth acerates in the fibre, sometimes accompanied by 

 partially-projecting slender acuates ; spined cylindricals or 

 acuates echinating the fibre. No flesh-spicules. 



EcMnodictyum rugosuniy n. sp. 



Stipitate, palmato-digitate. The short stem surmounted by 

 a broad flattened expansion. Height 7^ inches, breadth 5{ 

 inches, thickness ^ inch. Greyish yellow; hard, very 

 rugose, with conuli. Spicules : — (1) smooth acerates, sub- 

 hastately pointed, size '3 by "015 millim. ; (2) entirely spined 

 acuates (subspinulate), size '13 by •012 millim. (echinating). 



Locality. Station 190, south-west of New Guinea, 49 fath. 



EcMnodictyum asperum^ n. sp. 



Bushy, cavernous, coarsely aculeated. Height and breadth 

 about 2 inches. Deep chocolate-brown. Coarse and fibrous. 

 Surface glabrous where intact. Fibre stout, about '5 millim. 

 thick. Spicules: — (1) smooth, slightly curved, gradually 

 sharp-pointed acerates, size '35 by '0063 millim. ; (2) straight, 

 tapering, bluntly-pointed, entirely spined acuates, size "17 by 

 •0075 millim. (echinating). 



Locality. Papeete Harbour, Tahiti, 20 fath. 



Family 4. Axinellidae. 



Skeleton typically non-reticulate, consisting of ascending 

 axes of fibres, from which arise subsidiary fibres radiating to 

 the surface. Fibres typically plumose. Skeleton-spicules 

 chiefly acuate, to which acerates and (or) cylindricals may be 

 added. Flesh-spicules rarely present, never anchorates. 



Genus Hymeniacidon (Bowerbank). 



Skeleton reticulate, of ill-defined spiculo-fibre, not plu- 

 mose. Skeleton-spicules acuate or subspinulate. 



[Hymeniacidon carmicula, Bowerbank. 

 Locality. St. Vincent, Cape Verd Islands, shallow water.] 



* This genus is inserted here on the supposition that it has had ancho- 

 rate spicules and lost them. 



