172 



Family Desmanthidae 



Monanthus plumosus, gen. et sp. nov. 



Older CHORISTIDA. 

 F'amily TheneidaB. 



Triptolemus incertus, sp. n. 



Diseodermia natalensis, sp. n. 

 Plate iv., fig.-!. 2, 2a-k, and H, 3a-d. 



Sponge cup-shaped, sub-pedicellate. Outer or poral surface 

 smooth, showing a line branching venation ; inner or oscular 

 surface showing broad bands of minute circular oscules, and 

 beneath the surface, lines of orifices of excurrent canals 

 radiating from the base to the edge of the cup. Pores in 

 groups of two, three, or four, in sub-circular pore areas 150 m in 

 diameter ; oscules in oscular areas about 250 a* in diameter, 

 usually one, but occasionally two oscules in each area. 



Spicules. Alegascleres. — Desma with cylindrical smooth 

 or slightly tuberculated epactines (100x3 /') dividing into much 

 tuberculated branches, the tubercles cylindrical with flattened 

 summits or forming sharp ridges ; crepidial axes, each 55 f«. 



Phyllotriaene of poral surface : rhabdOme 90 /«, conical, 

 pointed ; cladome tetracladose, the branches enclosing almost 

 circular pore areas ; protocladi 90 /*, deuterocladi 60 m, tritocladi 

 from 60 — 100 A* ; crepidial axes about 40 a*. 



Discotriaene (or modified phyllotriagne) of oscular surface 

 with irregularly lobed disk, sometimes giving off three unequal 

 cladi ; crepidial axes about 30 m. 



Style 360 X 7*5 ^^, in sparsely scattered bundles near and at 

 right angles to the surface. 



Oxea 750 X 6 M, slender, straight or irregularly curved. 



Tyle 140 X 5 A*, head 6 m in length and width, neck 4*5 /*, 

 scattered about in the tissues. 



(These small tyles might be included among the micro- 

 scleres). 



Microscleres. — Microxea 80 x i m, slender, straight, smooth. 



Microstrongyle 20 x 3 m, straight, fusiform, with granular 

 surface. 



Colour dull white, texture hard. 



Localities : The type specimen from Natal coast (O'Neil 

 Peak bearing N.N.W. ^ W., distant 8 miles j, depth, 55 

 fathoms ; bottom, broken shells. 



A second specimen (much worn) also from Natal (Cape 



