[902] 



Whiteaves On the Genus Trimerella. 



4: 



Explanation ok the Plates. 

 Plate II. 



Fig-. I. Trimerella Equanensis. Outline of a brachial valve with part of the 

 lest preserved, partially restored and slitfhtly reduced in size. 

 The vertical line to the left shows the actual length. 



Fig. 2. Trimerella quanetisis. Outline of a cast of the interior of a large 

 brachial valve, slig^htly restored and reduced a little in si/.i;. The 

 vertical line on the rig-ht shows the actual length. 



Plate III. 



Fig-. I. Trimerella Equanensis. Outline of a nearly perfect pedicle valve, 

 slig-htly restored and reduced in size. The vertical line on the 

 left shows the actual size. 



F"i.g. 2. Trimerella borealis. Outline of the supposed dorsal side of a cast of 

 the interior of both valves, showing the impress of the brachial 

 valve. Of the natural size and slig-htly restored. 



Fig. 3. Trimerella borealis. Outline of the presumably ventral .side ot the 

 same specimen, showing the markings on the pedicle valve. 



Ottawa, Aug. 22, 1902. 



