PLATE XXVII. 



(With the exception of figure 7, all the specimens figured 

 on this plate are from the Silurian rocks of the Ekwan 

 River.) 



Spieifee CEISP0S if) Var. (page 253). 



Figure 1. Ventral view of a, small Spirifer, with narrow and angularjribs, that is 

 thought to be possibly a local variety of S. crispus. 



ReTICU LABIA SEPTENTBIONALIS (page 253). 



Figure 2. Dorsal view of a large but imperfect specimen of this species, that was 

 evidently a little longer than wide, when perfect. 



Figure 3. Dorsal view of a more perfect but rather smaller specimen of this species, 

 that is a little wider than long. 



Figure 4. Dorsal view of a nearly perfect but much smaller specimen. 



Figure 5. Dorsal view of a still smaller specimen. 



Meeistina (?) BXPANSA (page 245). 



Figure 6. Dorsal view of a large and presumably adult specimen of this species. 

 11 6 a. Front view of the same specimen, shewing the unequal convexity of the 

 two valves, and the absence of any mesial fold or sinus. 



Figure 7. Surface markings of part of the exfoliated test of a rather smaller speci- 

 men, from the Silurian rocks of the Attawapiskat'River ; five times 

 the natural size. 



Mytilaeca peenoides (page 255). 



Figure 8. Side view of the type and only known specimen of this species, a testi- 

 ferous left valve. 



Ctenodonta subovata (page 256). 



Figure 9. Side view of the only specimen known.to the writer. 



M 9 a. The same specimen, as viewed from above, shewing the amouno of con- 

 vexity of the closed valves. 



