[DAWSON] FOSSIL SPONGES AND OTHER ORGANIC REMAINS 



117 



Many fragments of this species liave been tbund from time to time, 

 showing long stout tapering anchoring-rods with masses of long slender 

 simple spicules near them ; hut in 1895 for the first time nearly perfect 

 specimens were observed. They consist of discs somcAvhat larger than 

 those of >S'. sancta, made up of fine straight S2:»icules radiating from a point 

 near one side and rather coarser than those of S. smicta, and showing 

 here and there a tendenc}^ to be aggregated more densely as if in bundles, 

 but this is not very marked. At and toward the circumference there are 

 occasionally a few very small cruciform spicules which, as they are not 

 confined to one specimen, I regard as probably the remains of an outer 

 or cortical layer. If the}' are accidental they must l)e the smaller spicules 

 of disintegrated Protospongia^ entangled in the spicular surface of Ste- 

 phanella. It seems more likely, however, that they are a part of its 

 structure, in which case it furnishes an example of a sponge with a dense 

 internal skeleton of radiating spicules. Fig. 27 represents a nearly 



Fig. 28.— Stephanella Hiwlii. P'ragment 

 with anchoring-rods. 



Fig. 29. Stephanella ? Anchoring- 

 rods and part of tlie spicules, enlarged. 



complete specimen, and Figs. 28 and 29 disintegrated fragments with the 

 anchoring-roots, which in some specimens are longer and more tai^ering 

 than in others, though always very stout at the liase. 



In Dr. Ami's specimens from Ottawa, a few stout anchoring-rods 

 and cruciform spicules are found in the same ^labs with Stephanella, but 

 none of them are seen to be attached. I think it not ijnprobable, how- 

 ever, that the former, at least, l)elong to Stephanella. 



