PLATE XXXIII. 



Unless otherwise stated, the figures in this and the following plates are 

 of natural size. 



Sph^erospongia tessellata (page 259). 



Figure 1. Hide view of a specimen in which none of the spicular head 

 plates are preserved, but which is otherwise nearly 

 perfect, shewing the general arraiigement of the 

 spicules, minus the head plates, and the meeting at 

 the aj)ex of the prolonged distal I'ays of the summit 

 spicules. Twice the natural size. 



Figure la. Portion of the .same, enlarged three times, to shew the mode 

 of interlocking of the spicules. 



Figure 2. Some of the spicular head plates of another specimen, enlarged 

 four times. 



Figure '^. Restoration of the species as it occurs in this region, the 

 details supplied fiom a numljer of specimens, which, 

 however, do not shew whether there was or was not 

 an ojiening at the apex, or whethei- there were or 

 were not any head plates to the apical spicules. 



Figure 4. 8ide view of a nearly cylindrical specimen. 



Figui'e -"i. Specimen with the basal plates preserved. Three times 

 natural size. 



Figure ^xi. Diagram shewing the shape and arrangement of the basal 

 plates. 



Figure 0. Outline of an aixuate and club-shaped specimen. 



Figuie 7. Outline of part of a slendei' specimen which is curved in two 



directions. 

 Figure '^. Outline of basal portion of a broadly conical specimen. 

 Figure 9. Outline of an imperfect suboonical specimen. 

 Figure 10. (Jutline of a subpj'riform specimen. 



The originals of all the figures on this plate, are from the shores or 

 isla)ids of Da-\\s(in Bay, Lake Winnipegosis. 



