20 THE SPONGES OF THE WEST-CENTRAL PACIFIC 



Text Figure No. 9. A portion of the fascicular fibrous skeleton of Polyfibrospongia 



dysodes, X 146. 



at the point of collection. I believe that the vast majority of the specimens 

 were Spongia and that Polyfibrospongia was the less common one. 



This is an irregularly massive sponge about 10 cm high and 13 cm in 

 diameter. The external color in life was dark gray, and the endosome was 

 drab. This species gave off" to a noticeable extent the characteristic odor of 

 the genus Ircinia as studied in the West Indies. Its consistency was very 

 spongy, but it was easy to cut this sponge. This is not true of the genus 

 Ircinia, which can be cut (even with a sharp knife) only with difficulty. 



The surface was conulose, with conules 1 mm high and 3 to 4 mm apart. 

 The pores are microscopic and closed. The oscules are about 6 mm in di- 

 ameter, not conspicuous. 



The ectosome is a thin, fleshy dermis, as in Spongia. The endosome is 

 dense, crowded with flagellate chambers about 25 li in diameter and spherical ; 

 these also resemble the flagellate chambers of Spongia, The endosome is 

 crowded with a reticulation of fibers, but these are much coarser than are 

 those in Spongia. 



The skeleton consists of ascending fibers which are pronouncedly fascicu- 

 lar. It is very difficult to measure them, because they blend into the surround- 

 ing reticulation somewhat, but they approximate 500 fx in total diameter. The 

 transverse fibers are about 100 [x in diameter, and they (as well as the ascend- 

 ing tracts) are loaded with foreign debris. The mesh is very coarse, with 

 openings about 1 mm in diameter. 



