CHAUNOPLECrELLA. CAVERNOSA. 67 



120 /^ but may lead down to 50/'. In general appearance the 

 discohexaster is very much like those I have figured from 

 Lanuginella ijvj)a in PL V., figs. 1, 2 and 4-ß, or from 

 Chaunoplectella spinifera in PL V., figs, lö and IG. In fact 

 the two last mentioned figures may just as well be considered as 

 representing the discohexaster-form in question from Ch. cavernosa. 

 From the end of each very short principal there arise three or 

 four, obsoletely tubercled or nearly smooth terminals, which are 

 each capped with a small convex terminal disc, pro\'ided with 

 7-9, minute marginal teeth. The terminals to each principal 

 diverge in such a manner that they do not form a separate 

 bunch but give to the entire rosette an approximately spherical 

 shape. — The form occurs numerously in all parts of the body in 

 the three small specimens (under 11 mm. height) shown in PL 

 v., fig. 9. It is somewhat more scarce in the nut-sized specimen 

 (ol mm. high) of PL \., fig. 8, though quite common in the 

 meshes of its basidictyoual plate. In three much larger specimens 

 (above 156 mm. in height) specially examined in respect of the 

 quantitative proportion of différent rosettes, the form a was found 

 missing, or at any rate exceedingly rare in the sponge-body proper, 

 though still commonly present in the basidictyoual plate remaining 

 on one (O. C. Ko. 106) of the said specimens. 



Form b represents intermediate phases between forms a and 

 c. It is larger than form a, measuring on an average, say, 200 

 ,« in diameter. In general appearance it is quite like the rosette 

 I have figured in fig. 14, PL V., from Chaunoplectella sjyinifera. 

 From the swollen end of each stout but very short principal, 

 there arise 2-4, long, slender and obsoletely rough or nearly 

 smooth terminals, which so\^diverge as to give a spherical shape 

 to the entire spicule. The terminal disc, it may be said, is made 



