70 A MONOGRAPH OP THE 



spicula projected at about right angles, to the surface ; 

 they are sub-fusiformi, acuate, or sub-spinulate. 



On the broad side, that was attached to the shell near 

 its distal portion, the longitudinal primary fasciculi were 

 no longer visible, but in place of them there were numerous 

 detached fasciculi of large fusiformi acuate and sub- 

 spinulate spicula, immediately beneath the surface, irregu- 

 larly crossing each other, but these fasciculi disappeared 

 near the centre of the body of the sponge, at about the 

 part where the primary longitudinal fasciculi were no longer 

 to be seen; but, on' the contrary direction, towards the 

 basal portion of the sponge there is a manifest tendency to 

 a disposition of the fasciculi in a radiant direction towards 

 its outer margin. On the adherent surface of the sponge 

 there appears to be but very few of the external defensive 

 spicula developed, and those which w r ere visible are in a 

 recumbent position. The aspect of the exterior broad 

 surface of the sponge is very different to that of the 

 adherent one ; here we have the whole surface bristling with 

 the small external defensive spicula, and in addition to 

 these there are large radiating clusters of long and stout 

 sub-fusiformi- acuate, or sub-spinulate spicula. They spring 

 from a closely compacted base and radiate thence at every 

 possible angle, giving to the surface a very remarkable and 

 beautiful appearance when examined in Canada balsam with 

 a power of about 100 linear. 



These radiating groups of spicula, and the profusion of 

 external defensive ones, that exist in the smaller of the two 

 specimens are nearly all absent in the larger specimen, 

 which appears as if it had been denuded by abrasion. In 

 the latter specimen, there are on the upper surface of the 

 body of the sponge several well-produced oscula and a 

 few smaller ones appear towards the distal portion of the 

 cloacal appendage ; but no such organs are to be found in 

 the smaller of the two specimens. 



