54 A MONOGRAPH OF THE 



abundantly with stellate spicula, and sparingly with the 

 minute and irregularly fusiform ones which abound in 

 the dermis. 



The stellate spicula are dispersed in considerable numbers 

 in that substance ; they are remarkably large in comparison 

 with those of Geodia ; an average-sized one measured nd 

 of an inch between the extremities of the radii, which vary 

 in number from three to ten or twelve. The ovaria 

 vary considerably in their proportions, those in a normal 

 condition are from one and a half to two diameters in 

 length ; an adult average-sized one measured, length ^th 

 inch, diameter 5 ^rd inch. In their natural state, when 

 viewed by direct light, they appear of the same colour as 

 the surrounding tissues, but when viewed as transparent 

 objects, the fertile ones present a dark central nucleus, 

 varying considerably in size in different specimens, and in 

 such ovaries the distal apices of the specula composing the 

 shell are usually acute, or more or less rounded, while in 

 the perfectly adult and fully developed ones, these ends of 

 the spicula have a truncated angulated form, and the surface 

 of the ovary has a smooth and even appearance, instead of 

 being composed of sharp projecting points, as in the young 

 and incompletely developed ones. After the discharge of 

 their contents, the central cavity becomes filled up by a 

 further development of the spicula inwards, and the process 

 is also frequently continued in an outward direction, until 

 the surface becomes tuberculated and distorted in a very 

 remarkable manner. 



