I'LATE II— Contlimeil. 



BARROISELLA, goii. nov. 



I'age 62. 

 BaRROISELLA SUBSPATUI.AXA, Moclc illicl Woi-lllCll. 



Fig. 14. The cardinal portion of tlie pedicle-vaive ; showing- the conspicuous pedicle-g-roove, which, in this 

 instance, has been somewhat widened by compression and fracture ; also tlie articular Tiosses 

 or cardinal fulcra on tlie basal margin. X 5. 



Fig. 15. The interior of a pedicle-valve ; showing the cardinal area, muscular and other markings. X 3. 



Fig-. It). The inteidor of a bi-achial valve,' with characteristic features. X 3. 



Black slate (Genesee slale). White Rimr, near RiicJcford, Indiana. 



LINGULASMA, Ulrich. 



Page 2t. 

 LiNGULASMA SCHUCHERTI, Ullicll. 



Fig. T7. The apical poi-tion of the intei-nal cast represented in fig. 22 ; enlai-ged to show the impression of 

 the pedicle-sheath (ps), or internal continuatiem of the cardinal area. X 3. 



Fig. 18. The interior of a brachial valve ; sliowing tlie (-haractei- of the musculai- impi-e.'isions, the platform 

 and the vei-y strong septum. Di-awn from a gutta-percha impression of an internal cast. 

 Natural size. 



Fig. ISI. Pi-otile view of an internal cast ; showing the i-elative thickness of the platforms on the two valves. 



Fig. 2U. The interior of the pedicle-valve; showing (he ))edicle-sheath (ps), the indislinctly defined muscu- 

 lar impressions, the low platform and inconspicuous septum. This dj-awing is also made frnm 

 a gutta-percha impre.ssion. Natui-al size. 



Fig. 21. An enlai-gement of the surface ornamentation. The tubei-cles are sharply defined, and round on 

 the median poitions of the shell, but liecome elongated and less distinct toward the lateral mar- 

 gins. X 5. 



Fig. 22. A natural cast ; sliowing tlie intei-ior of the brachial valve. 



Fig-. 23. The opposite side of the same specimen ; showing the internal characters of the pedicle-valve. 

 Hudson Rivei- group. Wilmington, Iliinois. 



LINGULOPS, Hall. 



Page 18. 



LiNGULOPS NoKwooDr, Jiinies. 



Fig. 24. The exterior of a pedicle-valve. X 4. 



Fig. 25. The intei-ioi- of a pedicle-valve, drawn from a gutta-jiercha impression of a natural cast. The 



pedicle-groove is faint but evident ; within the broad posterior margin lie the compound um- 



lional or cardinal impressions ; the scalloped posterior and the median muscular scars are very 



sharply defined. X 8- 

 Fig. 2H. The interior of a brachial valve ; showing the low, elongate platfoi-m. The punctae on the surface 



of tlie platform appear to be regularly arranged but are probably acciilental markings. 



Drawn from a gutta-percha impression. X ti. 



Hudson River g-roup. Cinnmmti, Ohio. 



L1NGULOF8 Whitfieldi, Hull. 



Fig. 27. The exterior of a pedicle-valve. X 6. 



Fig. 28. The interior of a pedicle-valve ; the original specimen. The figure has been dr.awn from a gutta- 

 ,; , percha impression of an internal cast, and shows the compound cardinal ai-ea (seen also in fig. 



■ 30), the inner portion of which is concentrically striated ; the crescent (cr) ; the scalloped pari- 



etal scar and median muscular scai-s ; the narrow longitudinal septum flanked by broad, rounded 

 i-idg-es continued from the visceral region. No traces of vascular imiiressions are vi.sible on 

 the specimen. X 12. 



Fig. 29. An imperfect interior, probably belonging to the same (pedicle-) valve. X 12. 



Fio-. 30. The interior of the brachial valve, drawn from a gutta-percha impression; showing the double 

 cardinal ai-ea, a faint pedicle-depression, the crescent (cr), the parietal (?) scars, the platform, 

 and the vascular sinuses with their outer ramifications. X 10. 



Hudson River group. Maqnoketa Creek, 12 miles Twrth-west of Dtibtique, Iowa. 



