PLATE III—Continued. 
ELKANIA, Ford. 
Page 75. 
Elkania desiderata, Billings (sp.). 
Fig. 15. The interior of a pedicle-valve ; showing the deep central impression (pedicle-pit of Ford), sub¬ 
cardinal, crescentic and external scars, the diverging vascular (genital ?) furrows and the broad, 
deep lateral depressions, probably riot of muscular origin. X 3. 
Fig. 16. The counterpart of the same, similarly enlarged. 
Fig.' 17. The interior of the brachial valve, with the impressions 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 granulose surface. X 6. 
• Quebec group. Pointe Livis. 
The above figures are made from Mr: E. Billings’ original specimens of the species. 
DISCINOPSIS, geu. nov. (Matthew). 
Page 105. 
Discinopsis Gulielmi, Matthew. 
Fig. 20. The exterior of a pedicle-valve 1; showing the radiating and concentric lines, and a flattened apex 
which may indicate the position of the foramen. X 5. 
Fig. 21. The interior of the pedicle-valve, with the linguiform median extension sharply defiried, and show¬ 
ing the possible position of the foramen. X 5. 
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 Brunswick. 
ACROTHELE, Linnarsson. 
Page 98. 
Acrothele Matthewi, Hartt (sp.), var. prima, Matthew. 
Fig. 25. The exterior of the pedicle-valve ; showing the character of the surface ornamentation. X 3. 
Acrothele Matthewi, Hartt, var. lata, Matthew. 
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. Profile of the latter. X 3. 
St. John group. Hanford Brook, New Brunswick. 
Acrothele Matthewi, Hartt (sp.). 
Fig. 29. The interior of a brachial valve ; showing the median septum and adjacent muscular scars. X 3. 
St. John group. Portland, New Brunswick. 
Figs. 25 to 29 are from the original specimens figured by Mr. 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 brachial valve with a faint median septum. X 2. 
Middle Cambrian. Antelope Springs, Utah. 
