452 DR. J. S. BOWERBANK ON THE SPONGILLID^. [NoV. 24, 



the corresponding spicula in Spongilla alba, Carter, from the water- 

 tanks of I3ombay ; but the truncated cyUndrical spines are longer 

 than in that species. In S. Baileyi, near the middle of the spiculum, 

 they often equal and sometimes exceed in length its greatest diameter. 

 Fig. 22, pi. 24, 'Phil. Trans. London' as above quoted, serves well 

 to represent the general character of these spicula. 



I have much pleasure in dedicating this interesting species to the 

 memory of one who has done so much, and in so able a manner, to 

 develope the microscopical natural history of his country, and who 

 was ever ready to assist his brother naturalists in any quarter of the 

 globe, either with material for examination or with information 

 from his rich stores of knowledge. 



Spongilla gregaria, Bowerbank. 



Skeleton-spicula cylindrical, stout, and rather short. Ovaria 

 furnished with an envelope ; spicula of the envelope few and scat- 

 tered, cylindrical, short and stout, entirely spined. Ovaria, surface 

 even, furnished abundantly with very short birotulate spicula ; ro- 

 tulse flat, margins entire, outer surface umbonate ; umbo very short, 

 slightly convex. Shaft of spiculum cylindrical, short, and stout. 



Colour, dried state, dark lurid green. 



Hab, River Amazon, on branches of trees periodically pendent in 

 the water, near Villa Nova. 



Examined in the dried state. 



All that I have yet seen of this species consists of small patches 

 of ovaria, varying from -1-th to ^^ths of an inch in diameter, of a 

 single layer of ovaries partially surrounding the small branches of 

 trees pendent in the water of the River Amazon at certain seasons 

 of the year. These little patches of ovaria look very like groups of 

 the eggs of flies the larvae of which are aquatic, and which are so 

 frequently to be seen on the small stems and branches at the margin 

 of ponds and rivers. On examining them with a Lieberkuhn, and 

 power of one hundred linear, it was at once apparent that they were 

 not ovaria of the Sponc/illa that occupied the greater part of the 

 stem on which they were seated — S. reticulata. I therefore pro- 

 ceeded to a regular examination of them, and soon satisfied myself 

 that they belonged to an entirely new species, with the mass of the 

 Sponge of which I am still unacquainted ; but from the well-marked 

 characters to be derived from their structure and the small portion 

 of the skeleton connecting them together, I have been enabled to 

 give a provisional description that will serve to give a standing to 

 the species until a better acquaintance with the entire Sponge 

 allows us to complete the characters. 



The spicula of the skeleton are cylindrical and smooth, and very 

 little larger than those of the envelope of the ovaries. They vary 

 somewhat in size, and occasionally the rudiment of a spine or two 

 may be detected upon them ; but this may perhaps be induced by 

 their being so closely connected with the envelope of the gemmule, 

 and occurring only in the short cylindrical portions of skeleton con- 

 necting the gemmules together ; and I am the more inclined to this 



