SPONGES — WHITELEGGE. 505 



ALLANTOPHORA, gen. nov. 



Sponge branched ; skeleton reticulate ; fibres with a moderate 

 amount of spongin, cored and echinated by smooth monactinal 

 megascleres. Microscleres :— sigmata, microxea, and micro- 

 strongyla. 



ALLANTOPHORA PLICATA, sp. nov. 



(Plate xlv., fig. 28.) 



Station 53. 



Sponge composed of an intricate mass of flattened branches ; 

 their edges are directed outwards ; they are acute, and finally 

 terminate in long acuminate points. Centrally the various 

 lamellate branches are here and there coalescent, from base to 

 summit, so that a transverse section would present an irre- 

 gular honeycombed structure with wide cells. The specimen is 

 130 mm. in height, 90 mm. in its greater and 60 in its lesser 

 diameter. The branches vary from 3 to 10 mm. in thickness and 

 from 10 to 30 mm. in width. The surface generally presents a 

 series of highly conulose, longitudinally disposed ridges, between 

 which numerous pores are situated ; they vary from round to 

 oval or elongate, and are from 3 to 5 mm. in diameter. The 

 pores are enclosed by thin fibrous walls, which are fringed with 

 slender conulose processes about 5 mm. long and 2 or 3 mm. 

 apart. The sponge is somewhat water worn, and the dermal 

 layer is only visible here and there as a thin transparent mem- 

 brane covering some of the pores ; this epidermal film is richly 

 furnished with microscleres, including sigmata, microstrongyla, 

 and microxea. Texture hard, inelastic, tough, and presenting a 

 coarse, fibrous surface ; colour greyish-yellow. 



Skeleton centrally reticulate, with oblong or elongate mesh ; 

 apically or laterally there is a tendency to become plumose. The 

 primary fibres consist of a moderate amount of pale spongin, 

 cored with dense whispy bundles of smooth styli ; their diameter 

 varies from 02 to 04 mm., and they are usually about 0-6 to 

 0'6 mm. apart. The secondaries are similar to the primaries, 

 but slightly thinner ; the connecting fibres are few and far 

 between except in the central region, where they measure from 

 0-05 to 0-1 mm., and are cored with six or more spicules in a 

 row. All the fibres are abundantly echinated by smooth styli, 

 which are usually disposed at right angles, but occasionally they 

 occur in subradiating tufts consisting of several spicules. 



