ART. 4 



SPONGES OF CALIFORNIA DE LAUBENFELS 



127 



mass permeated by dendritic fibers, and all set on a tough basal plate 

 of spongin. Ascending fibers, SO^u, to 200/x in diameter, without for- 

 eign inclusions, with lamellate structure, and terminating above in 

 the conules. (Fig. 79.) 



R&niarhs. — Because of the enormous quantities of siliceous matter 

 present (mostly foreign sjDicules) and because of the extreme opacity 

 of the cells (they are packed with purple granules that are almost 

 black), the difficulties in studying this sponge were excessively great. 

 Recourse was had to hydrofluoric acid as a solvent for the siliceous 

 matter, but the resulting material was badly shriveled and distorted, 

 so that the method helped very little. By dint of making many 

 sections some data can be given, however. There is a basal plate of 

 spongin from which dendritic processes rise. These are typically 

 about 130/x in diameter near the base, and about 0.8 to 2.7 mm high, 

 with occasional branching but no anastomosing. The spongin is 

 now dark, perhaps stained by coloring 

 matter dissolved into the alcohol from the 

 cells. Near the base these fibers are rather 

 obviously cored wnth pitli, but their struc- 

 ture is in general that of several concentri- 

 cally placed cones, a hollow within the 

 inner, smallest ones. This organization of 

 fiber is quite typical of the genus AphjsRIa. 



All through the flesh are enormous 

 quantities of spicules. It would seem that 

 every species in the vicinity was repre- 

 sented. There is but cramped space left 

 for the protoplasmic structure. As the 

 spicules are placed to avoid closing the 

 dermal pores there is at the surface that which resembles a reticula- 

 tion of foreign spicules, densely packed. From the ease with which 

 these are macerated apart, I judge they are not held together by 

 spongin. I find no foreign inclusions in the fibers themselves. 



Very careful search was made for the flagellate chambers. I be- 

 lieve that in this sponge, on account of the small size of the inter- 

 stices between spicules, the flagellate cells are poorly organized into 

 chambers. I find a few that seem to be eurypyllous, about SO/i, wide 

 by 100/x long. Others in this section are round, and about 30/^ in 

 diameter. These may be cross sections of the eurypyllous ones. 



On all counts, the closest species to polyraphis is violacea Lenden 

 feld (1883, p. 237), from Australia. It had sand grains in its basal 

 plate of spongin, wdiich I think is probably true of polyraphis. 

 From it and all others of the genus, however, the California sponge 

 is very widely separated by its profusion of foreign spicules. 



Figure 79. — Aplysilla p ol y- 

 raphis de Laubenfels, X 50 ; 

 section of macerated skele- 

 ton ; free-band drawing 



