I'J.ATE III— Continueil. 



ELKANIA, Ford. 



Page 75. 



Elkania desiderata, Billings (sp.). 



Fig. 15. The interior of a pediole-valve ; showing- the deep centi-al impression (pedicle-pit of Ford), sub- 

 cardinal, crescentic and extei'nal scars, the diverging vascular (genital ?) fui-rows and the broad, 

 deep lateral depressions, probably not of muscular origin. X 3. 



Fig. It). The counterpai't of the same, similarly enlai'ged. 



Fig. 17. The interior of the brachial valve, with the impi-essions of the central and lateral muscles and 

 crescent. X 3. 



Fig. 18. The counterpart of the same ; showing the muscular callosity or incipient platform. , X 3. 



Fig. 19. An enlargement of the surface of one of the. intermediate corneous layers of the shell; .showing 

 its irregularly gi'anulose surface. X B. 

 Quebec group. Pointe Llvis. 

 The above figures are made from Mi-. E. Billings' original specimens of the species. 



DISCINOPSIS, geii. uov. (iMatthew). 



Page 105. 



DisciNOPSis GuLiELMi, Miitthew. 



Fig. 20. The exterior of a pedicle-valve ? ; showing the radiating and concentric lines, and a flattened apex 

 which may indicate the position of the foi-amen. X 5. 



Fig. 21. The interior of the pedicle-valve, with the linguiforra median extension sharply defined, and show- 

 ing the possible position of the foramen. X S. 



Fig. 22. The counterpart of the same. X 5. 



Figs. 23, 24. Other interiors of the pedicle-valve, less satisfactorily preserved. X 5. 

 All are from the St. John group. Portland, New Brunswicli. 



ACROTHELE, Linnarsson. 



Page 9S. 

 AcROTHELE MaTTHEWI, Hilftt (-^p.), V;ir. PRIMA, Miitthew. 



Fig. 2.'5. The exterior of the pedicle-valve ; showing the charactei- of the surface oi-namentation. X 3. 



AcROTHELE Matthewi, Hitvtt, v;ir. LATA, Matlhcw. 



Fig. 26. The interior of the pedicle-valve ; showing the position of the foramen and the foraminal pits. X 3. 

 Fig. 27. An internal cast of the same valve. X 3. 

 Fig. 28. Pi-ofile of the latter. X 3. 



St. John group. . Hanford Brook, New Brunswick. 



ACROTHELE MAfTHEWI, Hailt (sp.). 



Fig. 29. The interior of a brac-hial valve ; sho-wing- the median septum and adjacent muscular scars. X 3. 

 St. John group. Portland, New Brunsioick. 

 Figs. 25 to 29 ai-e from the original specimens iigured by Mi-. Matthew. 



ACROTHELE SUBSIDUA, White. 



Fig. 30. The interior of the pedicle-valve ; showing the foramen and foraminal pits. X 2. 

 Fig. 31. The interior of the bi-achial valve with a faint median septum. X 2. 

 Middle Cambrian. Antelope Springs, Utah. 



