THE SPONGES OF THE WEST-CENTRAL PACIFIC 181 



The surface was very even and abundantly provided with pores, 60 ll to 

 70 ll in diameter. These are closeable with a sphinctate membrane. The 

 oscules could not be found with certainty. 



The ectosome consists of a special dermal structure, its spicules tan- 

 gentally placed. It is easily removed and underlain by extensive subdermal 

 cavities, as characteristic of the Halichondriidae. The endosome, as in the 

 species Halichondria, is like bread— in this particular case, like water-logged 

 or soaked bread. It contains a considerable quantity of filamentous algae 

 about 10 ll in diameter and indefinitely long. Its spicules are in confusion. 



The skeleton consists of megascleres of two categories, which are not defi- 

 nitely located in separate parts of the sponge. There are strongyles, 8 ll 

 by 225 ll, and there are long, sharp-pointed oxeas, varying from 1 ll by 

 300 ll to 4 ll by 300 ll in dimensions. These, especially the larger ones, are 

 very finely roughened, especially near the ends. 



The comparative relationships of the species have been discussed in 

 connection with the generic description. 



The species name is derived from the Latin word meaning "wet." 



GENUS HALICHONDRIA Fleming 

 Halichondria adelpha new 



Text Figure No. 120 



This species is here represented by the following: 



U.S.N.M. No. 22859, My No. M. 153, here designated as type, collected 

 July 7, 1949, by diver from the open ocean near the shore at Rube point 

 at Ebon Atoll. The depth was 3 meters, and the substrate was dead 

 coral. 



U.S.N.M. No. 22805, My No. N. 010, collected April 25, 1946, by J. P. E. 

 Morrison at Bikini Atoll in the central portion of the lagoon, 7 kilometers 

 south of the west end of Bikini Islet. It was dredged from a depth of 

 50 meters. It seems clearly to be an Halichondria, but the allocation to 

 adelpha is conjectural. The specimen is so small that it cannot be re- 

 garded as well known. 



The following description applies to the type specimen. 



This sponge is incrusting, 7 mm thick, extending laterally about 3 cm. 



The exterior and interior color in life was vivid orange and the con- 

 sistency rather mediocre. 



The surface is comparatively level, but abundantly supplied with minute 

 pits which are about 50 ll in diameter. These almost certainly represent the 

 locations of pores which have closed. There are no separations distinguish- 

 able between exhalant and inhalant apertures. 



The ectosome consists of tangent spicules, in a protoplasmic basis, 

 making a very definite dermis over subdermal spaces, as characteristic of the 



