246 ROYAL SOCIETY OF CANADA 



PLATE IV. 



Spirifee pennattts vab. Helena. 



Figure 1. — A partial mold of a brachial valve showing the form and the strong 

 plications bordering the median sinus. 



Figures 2, 5, 7, 8 and 9, Fragments showing the exterior form of the brachial 

 valve with its strong rounded plications bordering the median fold. 



Figure 3.— A mold of the exterior of the cardinal extremity drawn out to a 

 slender mucronate point, and showing the fine plications and the/ con- 

 centric lines crossing them. 



Figure 4. — An internal mold of umbonal portion of a pedicle- valve, showing the 

 prominent muscular scar. 



Figures 6, 12, and 13. — Molds of the exterior of fragments showing the form of 

 the fold and sinus. 



Figure 10. — A small fragment showing a trace of the slight longitudinal ridge 

 along the bottom of the sinus of the pedicle valve. 



Figure 11. — A fragment showing the longitudinal groove in top of the median 

 fold of brachial valve. 



Figure 14. — A large specimen showing the shell on the left half with its plica- 

 tions and mold of interior of right half, with the broad muscular scar 

 and the thickening of the cardinal margin under the beak. 

 All these specimens are from the same block from which the specimens figured 



on Plate III came from Cote St. Paul, near ISIiontreal. 



