PLATE XXXVIII. 



Pteeina lobata (page 292). 



Side view of the large.st specimen oollecteil, from a small island in 



l)a«son Bay, shewing the whole of the right valve and part 



of the left. 

 Side view of an im])erfert left val\e, from Dawson Kay, at Whiteaves 



Point. 

 Side ^'iew of an immature specimen of the left valve, from the western 



sliore of Dawson Bay, at the mouth of Steep Rock River. 

 Imperfect left valve of a \ery young shell, from Whiteaves Point, 



which may lie referalile to this species. 



Mytilaeca ixflata (page 29.'5). 



Figure C). Side view of the largest specimen collected, from the western shore of 

 Dawson Bay, at the nioutli of Steep Rock RiA'er, shewing the 

 right valve. 



Figure 6. Side \'iew of a small specimen, from a small island uortii of \\'hitcavcs 

 Point, in Dawson Bay, siiowing the left valve. 



Figure 6a. ^'entral aspect of the same. 



Myalina trigonalis (page 294). 



Figure 7. Side view of the only specimen i.:ollectcd, from Dawsou Bay, at the first 



small point north of the uu>uth of the Red Deei' River. 

 Figuie ~n. A'entral \'ie\\" i^f the same. 

 Figure "h. Dorsal view of the same. 



MoDiOMOEprrA compkessa (page 296). 



Figure 8. Side view of a cast of the interior of both valves, from the soutli- 

 eastern shore of Dawson Hay, at W'iiiteaves Pt)int, shewing 

 tile general shape of the left valve, tlie anterior muscular im- 

 pression, and a \'ery small portion of the test posteriorly. 



Figure 9. Side view of a similar east of another spcciuu'u, from tlic western shoic 

 of Dawson liay, at tlie moutli of Stcc)! Rock River. 



MoDiOMORPiiA TUMiDA (page 29(j). 



Figure 1(1. Side view of the largest specimen collected, xihich is a cast of the 

 interior of the slightly sc|)arate<l vah'cs, slicwing the general 

 shape of tlie right vahc, from the south-west side of Lake 

 Winnipegosis, at a small island oH' Weston Point. 



Figure 10a. Outline of tlie same, as seen from aliove. 



MllDIOMOEPlIA PARVULA (page 297). 



Figure I I. (!ast of the interior of the widely s|uead out valves of a specimen from 

 the western sliore of 1 >a,H son Bay, at tiie first small point 

 iiortli of the mouth of the Red Drei' River. 



Spathulla subrlliptkia (page 29S). 



Figure 12. Side view of a cast of the interior of lioth valves, from the western shore 

 of Dawson Bay, at the second small ]ioint uortli of the mouth 

 of the Rcil Deer River, shewing the general form of tlie left 

 vah e, anil indications of its .surface workiutts. 



