PLATE XXXII. 



Cyathothyllum Athabascense (page 202). 



Figure 1. Side view of the largest and most perfect specimen collected. 

 Figure la. Longitudinal section through the centre of the same. 

 Figure \h. Transverse section of the same, below the base of the cup. 



Spirifera tullia (page 224). 



Figure 'i. Dorsal view of a specimen from the Athabasca River. 

 Figure 2". Ventral view of the same specimen. 



Figure 26. Portion of the same, five times the natural size, to shew the surface 

 ornamentation of the ribbed lateral areas. 



Athyris Angelica, var. oocidentalis (page 227). 



Figure .3. Dorsal view of a specimen from the Athabasca River. 

 Figure 3ft. Ventral view of the same. 

 Figure ;Vj. Front view of the same. 



Figure 4. 

 Figure 5. 

 Figure 5a. 



Figure 6- 

 Figure 6a. 



Figure 7. 



Figure 8. 



Figure 9. 

 Figure 9a. 



Athtris parvula (page 228). 



Dorsal view of a specimen from the Athabasca River, three miles 

 below the Calumet, and referred to in the text as No. 1. 



Similar view of a specimen from the Athabasca River, thirty miles 

 below Red River, and referred to in the text as No. 2. 



Front view of original of fig. 5. 



Ptychopteria yHQuivALvis (page 239)- 

 Side view of the type specimen. 



Cardinal view of the same, to shew the ecjual convexity of the two 

 valves. 



Lbptodesma Demus (page 240). 

 A left valve of this species, from the Athabasca River. 



Leptodesma .Jason (page 240). 



Lateral view of a specimen of this species, from the Athabasca 

 River, showing only the left valve, though both are preserved. 



CoNDLARiA Salinensis (page 244). 



Side view of the only specimen collected. 



A portion of the same, five times the natural size. 



