4 THE CANADIAN NATURALIST. [Vol. viii. 



Fig. 1. — a. and b., ordinary skeleton-spicula. B., birotulate 

 spicula. The middle figure shows one end of a spiculum, of 

 about the ordinary form ; the lower figure, a type of deformed 

 spiculum which is common. All the above drawn from Lake of 

 the Woods specimens. Fig. 5. represents skeleton-spicula of a 

 specimen from the St. Lawrence. 



Spongilla Baileyi, Bowerbank. This species appears to be 

 indicated by a single birotulate spiculum, in the Lake of the 

 Woods collection. It was originally described by Dr. Bower 

 bank, from specimens obtained at West Point, N. Y. 



Spongilla asperrima, sp. nov. Sponge sessile, encrusting, 

 thin ; surface slightly undulated ; oscula rather large, scattered ; 

 skeleton-spicula, fusiformi-acerate, slightly arcuate, stout, densely 

 spined, with the exception of the extreme apices ; length, 0.01 

 to 0.009 in. These mixed with a few smooth and more slender. 

 Spines minute, acute. Ovaria sub-globose, diameter nearly 

 0.02 ; spicula birotulate, short ; rotulae equal in size, flat, very 

 deeply divided, about 0.0005 in., equal to, or greater than, the 

 length of the shaft ; radii not acute ; shaft with a distinct boss 

 at each end. 



Hah., River St. Lawrence, near Montreal. 



This species much resembles that from the Lake of the Woods, 

 of which, it is possible, it may turn out to be a variety. It differs 

 chiefly in its thicker, coarser and much more densely spinous 

 skeleton-spicula, and in the external form of the sponge. Not 

 possessing any intermediate forms, I have referred them, for the 

 present at least, to different species. The spicula are not unlike 

 S. Parfttii, as figured by Bowerbank,* but differ from them 

 about as much as from those of the Lake of the Woods. Many 

 of the skeleton-spicula are deformed, having crutch-like or bent 

 ends. 



Fig. 2., a., ordinary skeleton-spiculum. B., one of the ordi- 

 nary birotulate spicula. 



Spongilla flexispina, sp. nov. Specimens not large enough to 

 show the general form, or appearance of the surface. Skeleton- 

 spicula acerate to subfusiformi-acerate, very slightly arcuate to 

 nearly straight, smooth, not very acute, length about 0.0115 in. 

 Dermal and interstitial spicula subcylindrical, irregularly and 



♦Brit. Spongiadae, Vol. III., Plate LXXXVI. 



