THE SPONGES OF THE WEST-CENTRAL PACIFIC 13 



This is a subspherical sponge, 15 cm high and 15 cm in diameter. The 

 color of the ectosome in life was jet black, glistening and shiny. The endo- 

 some was drab, with here and there a small brick-red area. These reddish 

 patches gave indications that the sponge was in poor condition, perhaps patho- 

 logical or even moribund. The consistency was very spongy. 



The surface is conulose with conules 1 to 2 mm high and 3 to 4 mm 

 apart and very sharp in outline. The pores are 40 /x to 80 p. in diameter and 

 100 fi to 200 /x apart, center to center. The oscules occurred only on the 

 upper surface of the specimen and proved to be very contractile. They were 

 certainly about 1 cm in diameter when fully expanded but are much smaller 

 in the preserved specimen. They are numerous and scattered. 



The ectosome is fleshy and adherent, not easily removed. It contains 

 little or no debris. The endosome shows an obvious fibro-reticulation, so 

 coarse that it can be studied with the naked eye. As studied with the micro- 

 scope in section, the interior of the sponge proves to contain much mesogloea 

 or jelly. Numerous typical flagellate chambers occur; they are spherical and 

 25 fi in diameter. Groups of large cells are seen, each cell upwards of 20 /x 

 in diameter. These almost certainly are ova, although another possibility is 

 that they may already be zygotes. 



The ascending fibers are often as much as 50 jx in diameter, but some are 

 smaller. They are interconnected by smaller ones, some of these as little as 

 20 p. in diameter. Practically all are densely packed with foreign material, 

 chiefly fragments of spicules. After long search, one small fiber was dis- 

 covered to be free from such inclusion, but obviously was freakish. 



The only other species of the genus Heteronema so far erected, is 

 H. crecta Keller 1889, page 340, from the Red Sea. Obviously this is related 

 very closely to eubamma, but there are a number of differences. Erecta was 



Text Figure No. 5. A portion of the fibrous skeleton of Heteronema eubamma, X 182. 



