458 DR. J. S. BOWERBANK ON THE SPONGILLID^. [Nov. 24, 



Examined in the dried state. 



I am indebted to Mr. Robert Brown for my knowledge of this 

 interesting species, which he informed rae he believed was collected 

 from the River Amazon ; and from the similarity of its structure to 

 other species of Spongilla which I have received from Mr. Bates, 

 who collected them from that river, I am induced to believe the 

 locality is correct. 



The specimen is considerably mutilated, so that the natural size 

 and form cannot be determined with precision ; in its condition 

 when I first saw it in Mr. Brown's possession, it was about 3 inches 

 in length by \\ inch in breadth and thickness. The stem of wood 

 to which the Sponge is fixed, and which passes in a diagonal di- 

 rection through the portion which was kindly given to me by Mr. 

 Brown, does not much exceed a line in diameter ; and the attachment 

 is by an open network of flattened fibre, which embraces it closely in 

 all parts. 



The primary fibres of the Sponge are stout and nearly parallel to 

 each other, and do not, as is usually the case, radiate from the stem 

 of wood at right angles to its long axis. The secondary fibres uni- 

 ting the primary ones are irregular in their direction. The surface 

 is strongly spiniferous from the projection of the terminations of the 

 primary fibres, and the spaces between the spinous terminations are 

 open and entirely destitute of either membrane or reticular structure. 

 The skeleton-spicula are -^ inch in length, and their greatest dia- 

 meter is g-^ inch. 



The ovaries are situated immediately beneath and for a short 

 distance within the outer surface of the Sponge, and none were ob- 

 served more deeply seated. The attachment of the ovary-case or 

 envelope is not by an especial pedicel or a single point ; occasionally 

 it has two or three points of adhesion to the same fibre by short pe- 

 dicels, and it is often thus attached to two or more separate fibres, 

 or it has one broad sessile attachment to a single fibre. The surface 

 of the envelope is even, and there is no foramen on it, nor any indica- 

 tion of the position of that of the ovary within it. The ovary is 

 closely embraced by the strong spicular envelope, and small elongate 

 masses of its outer surface are projected, here and there, through the 

 interstices of the envelope, causing the latter to be more or less 

 tuberculous ; and from the smallness of the interstices the tubercles 

 are much greater in length than in thickness ; while in the nearly 

 allied species, S. Batesii, the tubercles of the ovarium-case are much 

 thicker than they are high, and the spicula of the envelope are nearly 

 twice as long as those of S. Brownii. The spicula of the envelope 

 are more regularly acerate than those of the skeleton : they vary 

 somewhat in size and degree of curvature ; the dimensions of two 

 that I measured were y^ ^^^^ ^ong by ygW ^^"^^ diameter, and 

 -y\^ inch long by yaVr ^^^^ diameter. They are disposed in a close 

 but irregular network, seldom exceeding two spicula in thickness. 



The scutulate spicula of the ovary are seated on the outer surface 

 of the inner membrane of that organ, with the umbo of the . scu- 

 tulura outward ; but in their natural condition they do not appear to 



