PLATE XVI. 

 Unless otherwise stated, all the figures are of the natural size. 



AULACOPELLA WiNNIPEGENSIS (page 145). 



Figure 1. Upper side of the specimen upon which the species is based. A-B, re- 

 presents a broken surface ; P, the mineral deposit in the Paragaster ; 

 (?'■, (t^ and O^, the wedge-shaped fillings up, by the matrix, of spaces 

 that were originally empty ; and A-G, a transverse section of part of 

 the specimen, at the midheight. 



IT 2. Restoration of the upper surface of the sponge, one-third the natural size. 



M 3. Restoration of the base of the same, also one-third the natural size. 



