62 



Canadian Record of Science, 





those which havecoiiHolidated spicules or firm external cor- 

 tex, are those most likely to retain their original forms. 

 Even the looser kinds of sponges, however, may under cer- 

 tain circumstances preserve their rotundity of fo:*m, in 

 which case thoy will usually show external markings, but 

 not so well internal structure, unless when sliced. On the 

 other hand, when completely flattened, which is usunlly the 

 case in shaly beds, only an outline of the form remains, and 

 sometimes not even this, while the forms and in part the 

 arrangement of the spicules are usually apparent. Ftirther, 

 the hollow and thin-walled species are more liable to be 

 completely flattened, though in some cases, as in the Devo- 

 nian DictyospongisB, they may retain their form. It was 

 this property, and the membranous appearance of the outer 

 coat, that for a long time sustained the belief that these 

 were plants rather than sponges. 



In the case of the sponges procured in the shales at 

 Little Metis, perfect flattening has occurred, and in many 

 cases the spicules have been separated, and appear as mere 

 spicular patches or layers. In other instances, however, they 

 remain approximately in their natural position, and even the 

 general outline of the form can be observed. The collec- 

 tions include several species of sponges, Hexactinellid and 

 Monactinellid ; but, so far as observed, one of them is more 

 abundant and better preserved than the others. The fol- 

 lowing may serve as a preliminary rough description of the 

 species collected, — which will be more fully described and 

 commented on by Dr. J. George Hinde, F.G.S., the author 

 of the British Museum Catalogue of Fossil Sponges. See 

 paper appended. . ; iv 



1. Protospmgia tetranema. S. N. (Fig. 1)' The general 

 form has been spheroidal, probably with an osculum or 

 oscula at top. Eoot composed of four long spicules in two 

 pairs, which diverge somewhat and then bend toward each 



^ This figure is a restoration, with two of the spicules enlarged. 

 The defensive spicules and osculum are conjectural, being based 

 merely on loose spicules and general form. 





