CEATEROMOEriTA MEYEllI TÜBEROSA. 69 



Summarily speaking, the general ajipeavance of the sponge 

 is essentially like that of the typical sj^ecies, except in the fact 

 already indicated that the external surface of the body proper is 

 irregularly and conspicuously uneven on accovuit of large and 

 small rounded protuberances. These are usually only slightly (tr 

 not at all developed along the rim <A' the cup-like body for some 

 distance from the thin oscular edge. Lower down and on the 

 remaining portion of the body, they exist in indefinite numbers 

 and distribution (typically as in text-fig. 1, U). Noteworthy is 

 the fact that in four cases I have found the bosses, scarcely 

 developed on one side of the body, instead of being j)resent all 

 around as is usually the case, so that that side ap[)ears neaidy 

 smooth. Further, in several specimens the body is found to be 

 laterally compressed to a greater or less degree, the osculum then 

 presenting a correspondingly oblong shape. The firm-looking 

 stalk, which is generally of an irregular outline in cross- section, 

 makes up l-h of the entire height of the sponge. It may be 

 covered over by a criist-like coating of dermal and hypodermal 

 peiitactins, which however are easily detached. 



Some of the freely open excuri-ent apertures on the gastial 

 surface (PI. V., fig. 13) are of a conspicuously large size. This 

 is owing to the larger caliber of the excurrent canals wliich 

 penetrate into the parietal Ijosses. AVlien such a canal is exces- 

 sively widened it may aj)pear more like a niche iii the wall of the 

 ii'astral cavitv than a tube, tliousi;h it seems that the boss alwavs 

 arises as a thickeninir of the wall and not bv an evairiuation nt' 

 this. The bottom of the gastral cavity is occupied centrally Ity 

 a space which peripherally runs out into radial septa-like ridges 

 and on which open com[)aratively small apertures leading into 

 the canal-svstem of the stalk. 



