EXPLANATION OF PLATE LXXIII. 



Figs. 1-5. SYRINGOTHYRIS CUSPIDATUS Martin. 



Anterior, pedicle, posterior, brachial and lateral views of a very 

 perfect specimen, introduced for comparison with our Ameri- 

 can species. (W. M., No. 12519.) 



Carboniferous limestone, Waulsort, Belgium. 



Figs. 6-7. SYRINGOTHYRIS (?) sp. 



Posterior and lateral views of a nearly complete specimen. (W. M., 

 No. 13961.) 



Chouteau limestone, Providence, Missouri. 



Figs. 8-10. SYRINGOTHYRIS BUSHEERGENSIS n. sp p. 391 



8. Posterior view of an incomplete internal cast of a pedicle valve. 

 9. Plaster cast from a natural mould showing the cardinal area 

 of a pedicle valve. 10. Internal cast of an incomplete pedicle 

 valve showing an impression of the syrinx. (W. M., No. 

 13970.) 



Bushberg sandstone, near Sulphur Springs, Missouri. 



162 



