SILICIOUS AND HORNY SPONGES WILSON. 405 



or only vaguely roughened, lacking the gnarled protuberances. Both 

 specimens are roughly cylindrical, 300-340 mm. high, 95-130 mm. 

 wide, diminishing somewhat above, the wall, 25-50 mm. thick, thin- 

 ning away to an edge at the mouth of the vase. One of them expands 

 below into a large solid base and the indication is (pi. 41, fig. 5) that 

 a second vase arose from the base but was sawn off. The sponges are 

 of the same heavy, woody character as the type; the color is the same, 

 and the canals are essentially similar. 



The fibers of the skeletal framework are like those of the type 

 but somewhat thicker, ranging up to 350^00 y. in thickness. The 

 framework is somewhat coarser than in the type, the meshes often 

 1 to 1.5 mm. wide. In neither specimen is the framework as regu 

 lar as in the type, although in the superficial region everywhere 

 fibers radial to the surface and connectives are distinguishable. The 

 individual differences have some interest and may be noted. Thus 

 in one of the two sponges (pi. 41, fig. 4), conspicuous long main 

 fibers, such as are present in the type, were not observed, the skeleton 

 consisting simply of a coarse irregular reticulum, with radial fibers 

 and connectives differentiated at both surfaces. In the other speci- 

 men (pi. 41, fig. 5) the base in its outer part shows radial fibers with 

 transverse connectives, giving large squarish meshes; internally 

 the skeleton of the base is irregular. In the wall of the vase long 

 ascending main fibers are present but their distribution is peculiar 

 and different from that of the type. Instead of arching over to- 

 ward both surfaces, they ascend just beneath the dermal membrane 

 of the sponge cavity, and arch over to the outer surface, thus pass- 

 ing completely through the wall of the vase. 



The dermal skeleton is as in the type, the meshes about 225 \l wide. 

 The coarser fibers of the superficial internal skeleton show through 

 the surface reticulum, and thus may seem at first sight to divide 

 it into a system of areas, each of which appears subdivided by the 

 strands of the dermal reticulum proper. 



The spicules are similar to those of the type and are distributed 

 in the same waj^, the very small ones forming small radially pro- 

 jecting tufts, closely set on the dermal reticulum. They do not 

 reach as large a size as in the type, the large spicules measuring 

 in one specimen (fig. 4) 240-280 [x by 11—16 p, in the other (fig. 

 5) 240-280 by 13-14 [x. They range down to very small ones of 

 about the same size as in the type. There are individual differences 

 between the two sponges as to the shape of the spicule ends. In 

 one specimen (fig. 4) the spicules, large and small, are almost all 

 oxeas with sharp points. In the other (fig. 5) the prevailing type, 

 both for large and small spicules, is the intermediate (©sea rounded 

 at the apices) ; but typical strongyles are common and there are 

 some sharp-pointed oxeas. 



