oftfii abruptly bc-iit, e'litiivly ^j)intMl, length nearly 0.003 in.; 

 spines scattered, rather largo, coiiieal, acute, neucrally retrorso 

 near the ends of the spicuhi. Ovarian splcula scarcely distin- 

 guishable from the interstitial and dermal. 



//"/a, Kiver St. Lawrence, near 3Iontrcal. 



This species is oi' the type of the European ,S'. hn-dstris, but 

 differs sufficiently from that species. It also differs markedly 

 from *y. Ddirsoiil and *S'. 0(h.i>r<i,usis. Its ovarian and dermal 

 spicula are intermediate in size between those of the last named 

 species. 



Fig. 4. — a., ordinary skeleton-spiculum. It., a second form of 

 skeleton-spiculum, smaller and perhaps not fully developed. 

 B., C, ovarian and dermal spicula. 



SpongiUa Offinnirii.sis, sp. nov. Specimens do not show the 

 external form. Colour in the dried state, green. Skeleton-spi- 

 cula aeerate, sligiitly arcuate, often rather abruptly and bluntly 

 pointed, smooth, length. 0.011 to 0.008 in. Ovaria sub-globose, 

 rather irregular, large, diameter 0.04 in.; spicula cylindrical, 

 stout, slightly and regularly arcuate, entirely and rather densely 

 spined, length 0.0034; spines rather prominent, somewhat ob- 

 tuse. JJermal and interstitial spicula like the ovarian, but 

 slightly more delicate. 



JJ<(b., L'Orignal, on the Ottawa lliver. 



The skeleton-spicula are shorter than those oi' *S'. Dm Miii ; 

 the ovarian etc. spicula much larger tlian those of that species, 

 and larger also than those of /S'. /f(xinjHn<f. They somewhat 

 resemble those of S. hiciistris. but are distinctly truncate at the 

 extremities. The specimens are small, but densely tilled with 

 large ovaria. . , t 



Fig. 0. — 'I., ordinary skoleton-spicula. A., ovarian spicula. 



