PLATE YI. 



Protocardia BdREALTS (page 41.) 



Fii;ure 1. Side view of a .specimen of averaiie size ami normal form, .sliew- 

 hvs the right valve. 

 \i.i. Dor.sal outline of the .same. 

 " L'. Side view of another .specimen, in which the valves are un- 

 usually tumid and ineijuilateral. 

 " 'Id. Dorsal outline of tlie last. 



" :!. Cast of the interior of a large specimen from Ross (Joulee, 

 shewing the outlines of the musiuilar impressions of tlie 

 right valve. 



CALf.isTA (i»osiNioi\sis) Deweyi (pagc 42). 



l'"ii;-ure i. Side view of a supposed large variety of this sjiccies, from near 



lUg Plume Creek, shewing the left valve. 

 " .'I. (Jutline of a cast of the interior of another form of the specie,s, 



from Bull's Head, shewing the impreBsions nf the pallial 



.sinus and muscular impressions of tlie right valve. 

 " .")'(. Outline of portion of a left valve from the same, locality as the 



last, to shew the lunge dentition of that valx'c. 



Panop.ea subovalis (page 44). 



Figure <>. Side view of the type specimen, shewing the right valve. 



" V,ii. (Jutline of tlie same as seen from above, to illustrate the com- 

 parative convexity of the shell, the anterior and posterior 

 gaping extremities, and the short ligamental area. 



