Silurian and Devonian Fossils of Canada. 



443 



been able to refer the species for which the above generic name 

 is proposed to any of the described genera. Although several 

 sihcified specimens exhibiting the interior have been obtained, 

 they do not show any muscular impressions. The perforation on 

 the back of the beak was at first supposed to be a fracture, but 

 we have now specimens which exhibit its characters so complete, 

 ly that I do not think it possible there can be any mistake. The 

 internal structure of the larger valve somewhat resembles that of 

 Pentamerus or Ca?narophoria, the concave plate beneath the 

 beak appearing to be the homologue of the floor of the triangular 

 chamber found in these genera. I cannot make out however, 

 that it is in any way connected with the mediodongitudinal ridge 

 as is the case in both Pentamerus and Camarophoria. In remov- 

 ing the limestone from silicified specimens the delicate processes 

 in the interior of species of brachiopoda are very often destroyed, 

 and it is possible that the connection in question may exist in per- 

 fect specimens, but not appear after treatment with acids. It is 

 therefore uncertain whether or not it is attached to the plate be- 

 neath the beak. If it should be hereafter ascertained that it is so 

 connected, the foramen on the umbo would still be sufficient to 

 show that this is a new genus, to the establishment of which the 

 characters of the smaller ' ; alve and the absence of any articulating 

 and apophysary apparatus would be additional characters. As 

 other specimens can be procured and as the internal characters 

 cannot be well shewn by wood-engraving, I shall for the present 

 give figures of the exterior only. 



ElCHWALDIA STJBTRIGONALIS (Billings.) 



A 



Fig.' 24. 



Figure 24. A, dorsal view ; B, ventral ; C, side ; D, front ; E, apex, 

 ahewina- the foramen. 



