Bekdk.] Carboniferous Invertebrates . 181 



PLATE XI. 



Productus enra, (p. 75.) 



1. Pedicle valve of the common form. Natural size. 

 16. Cast of pedicle valve. (After Hall.) 



lc. Brachial valve, interior view, showing traces of brachial markings. 



Natural size. 

 Id. Pedicle valve of large specimen. Natural size. 



le. Spine as seen on a slab of shale, from a large specimen. Natural size. 

 If. Pedicle valve of broad, large variety. Natural size. 

 Productus eora amerlcanus, (p. 77.) 



2. Pedicle valve of typical form. Natural size. 

 Productus punctaius, (p. 87.) 



3. Interior of brachial valve, showing adductor scars. Natural size. 

 Productus costatus, (p. 79.) 



4. Cast of pedicle valve, view of beak. Natural size. 

 Clclothyris royssii, p. 104.) 



5. Outline of specimen with nearly straight hinge. 



56. Brachial valve and beak of pedicle valve of specimen. 

 5c. Lateral outline of specimen. All natural size. 

 Aulacorhynchus millepunclatus, (p. 89.) 



6. External view of one of the valves. (After Meek and Worthen.) 



PLATE XII. 



Aulacorhynchus millepunctatus, (p. 89.) 



1. Interior of brachial valve. (After Meek and Worthen.) 



16. View of a specimen from Kansas City, showing indications of extra plat- 

 forms, and probably a different species. Natural size. It is quite 

 convex for the genus. 

 Clelothyris royssii, (p. 104.) 



2. Side view of more robust specimen. Natural size. 

 Hustedia mormon?', (p. 103.) 



3. Hinge apparatus. (After Hall.) 

 Reticularia perplexa, (p. 102.) 



4. Pedicle valve. About natural size. 

 46. Opposite valve of same. 



4'-. Side view of same. 



\d. Surface enlarged. ( After Grity.) 



Spirifer camera tus, (p. 99.) 



5. Interior of brachial valve, showing sockets for cardinal teeth. Natural 



size. 

 56. Pedicle valve of long-eared form. 

 •>. Brachial valve and hinge area of robust form. 

 •V/. Young specimen. All natural size. 

 •">' . Spire of one of this species | broken). Natural size. 



