PLATE 95. 



Fig. 1-7. Orthis musculosa. 409 



1. Dorsal view of a specimen preserving the sliell. Tlie strise are partially obliterated by the 



silicificatioa of the shell, and they are not sufficiently curved towards tlie hhige-line in 

 the figure. 



2. Profile view of the same specimen. 



3 & 4. Dorsal and ventral views of a smaller specimen. 



5. Interior of the ventral valve. 



6. Interior of the dorsal valve. 



7. Cardinal view of the dorsal valve, showing the outline and the elevation of the processes. 



Fig. 8. Strophodonta magnifica, 414 



8. A cast of the ventral valve, showing the muscular impression in part, with the shell pre- 

 served upon the lower part of the specimen. 



Fig. 9. Strophodonta magniventra. 411 



9. This figure is an impression taken from a mould in sandstone, left by the solution and re- 

 moval of the shell. The broad reniform muscuLar impressions are strongly defined by an 

 elevated rim; and between these and the median crest there are, on each side, other 

 equally marlicd impressions, which, with the fliittened median crest, appear to liave been 

 the points of attachment for the adductor muscles. Below and outside of these are vascu- 

 lar impressions approaching those of Pkoductus, which are strongly marked, but not 

 limited as the others. 



Fig. 10. Strophodonta vascularia. 412 



10. A cast of the dorsal valve from an impression in sandstone. The divisions of the cardinal 

 process are not of the full length, owing to the cavities not becoming filled with the ma- 

 terial forming the cast. 



