4 DR. J. S. BOWERBANK ON THE SPONGIAD.E. [Jan. 7, 



and simple cylindro-stellate with comparatively long radii ; small 

 ones cylindro-stellate with very short radii. Skeleton-spicula fusi- 

 forrni-cylindrical. Ovaria oval, variable in form. 



Colour light cream-yellow. 



Hab. Port Elliot, Australia {Mr. Ray). 



Examined in the dried state. 



I received this sponge with a considerable number of others of 

 various genera from the Murray River, Australia, where they were 

 collected by Mr. Ray. The specimen is an irregularly oval mass 

 If inch long, 1| inch greatest breadth, and l^inch high. On cutting 

 off a portion of the sponge to examine its structure, I found the 

 interior to be one large cavity, the parietes of the sponge not ex- 

 ceeding four lines at the thickest part, and near the basal portion 

 about one line in thickness only, the excurrent canals running in 

 a tortuous direction through the sponge to the oscula. The inner 

 surface presented an irregular matting of spicula on membranous 

 tissue, differing in no respect from other portions of the interior 

 membranous structures. 



The occurrence of this large cavity is interesting, as a similarly 

 cavernous condition prevails in the type specimen of the genus, 

 Geodia gibberosa, in the Paris Museum. I do uot consider this 

 hollow condition of such specimens the normal state of the sponge, 

 and I should not expect to find it of common occurrence in this or 

 any other species of the genus ; it is probable that it is only in 

 young and incompletely developed specimens, or by the accidental 

 action of drying, that it would be found to occur. 



The surface characters of the sponge are unfortunately nearly 

 obliterated, apparently by maceration and attrition. No portion of 

 the dermal membrane is preserved. Sections at right angles to the 

 surface exhibit the remains of a few large spicula that have passed 

 through the dermal crust and have been projected about one-third 

 of their length beyond the surface, which in its natural condition 

 was therefore more or less hispid. The connecting spicula are few 

 in number and very irregularly disposed, and the terminal radii are 

 more frequently simple than they are dichotomous. The spicula of 

 the skeleton vary considerably in their proportions ; and the greater 

 part of the ovaries have the apices of the radial spicula of which 

 they are composed more or less acute. From the whole of these 

 circumstances combined, it may naturally be inferred that the speci- 

 men is not in a fully matured condition. 



The connecting spicula are exceedingly various in form. In their 

 early state they are simple expando-ternate ones ; as they advance 

 in size one or more of the rays exhibit symptoms of bifurcating ; and 

 you may thus trace their progressive development until they attain 

 the size and proportions of the fully developed spiculum represented 

 by fig. 3, Plate I. In the completely developed condition they are 

 not very numerous ; nor, indeed, are they abundant in any state. 



The recurvo-ternate spicula are very slender in their proportions, 

 and their shafts are usually exceedingly long. 



