144 ART. 7. 1. IJIMA : HEXACTINELLIDA, IV. 



general shape being tlien not unlike that of the Rhahdocalyptus 

 shown in PL XYIT. The Imds are sometimes represented merely 

 bv secondary oseula which are iinaccomjmnied by any outbulging 

 of the surrounding parts and thus appear like simple gaps in the 

 wall. Thus, the specimen marked B in text-figure 6 is in pos- 

 session of more than one small sucli osculum in addition to the 

 large primär}^ one at the superior end. 



The species grows to very considerable dimensions. The 

 largest complete specimen before me (S. C. M, No. 432) is 432 

 mm. high, and consists of two large persons and of a l)OSS-like 

 cœcnm of the size of one's fist, all these parts arising from a 

 common basal portion. There is also in the Science College a 

 larger fragment with an osculum measuring 240 mm. in diameter. 

 On the other hand, the smallest individual I have seen was only 

 al)out the size of a walnut. 



A striking feature of the sponge consists in the sharply 

 apexed conical elevations of the external surface. These occur 

 at various but leather wide intervals. They are usually most 

 numerous, largest and tallest near the middle or in the lower 

 half of the body. In large specimens they may be as high as 

 25 mm., but are much shorter in the smaller specimens. They 

 grow more and more sparse superiorly towards the osculum, 

 becoming at the same time smaller and more inconspicuous, until 

 they no longer exist close to the oscular margin. 



The cones l)ear on the apex moderately strong, needle-like 

 prostalia lateralia, which project either singly or in tufts of a 

 few together to various lengths, up to about 20 mm. They are 

 directed on the whole radially, though frequently inclined obliquely 

 one way or the other. When the prostalia are well preserved, 

 as is especially the case in the smaller specimens, the resemblance 



