I'l-ATK III— Continuect. 



ELKANIA, Ford. 



Page 75. 



Elkania desiderata, Billings (sp.). 



Fig. 15. The interior of a jieiUcle-valve ; showing- the deep central inipi-ession (pedicle-pit of Ford), sub- 

 cardinal, crescentic and external scars, thedivei'ging vascular (genital ?) furrows and the broad, 

 deep lateral depressions, jirobably not of muscuhi.r orifrin. X 3. 



Pig. It). The counterpart of the same, similarly enlarged. 



Fig. 17. The interior of the brachial valve, with the impressions of tlie cenfral and latei-al mn.scles and 

 crescent. X 3. 



Fig. 18. The connterp.art of the same ; showing the muscular callosity or incipi(uit platform. X 3. 



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

 its irregularly granulose sui-face. X 6. 

 Quebec group. Po'mte Livis. 

 The above figures are made from Mr. E. Billings' original spec'iinens of the species. 



DISCINOPSIS, gen. nov. (Matthew). 



Page 105. 

 DiSCINOPSIS GULIELMI, Mllttlu'W. 



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 exten.sion sha.i-ply 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 •'). 

 All are from the St. John group. Portland, JVew Biiiii^wivk. 



ACROTHELE, Linnarsson. 



Page 98. 

 AcROTHELE MaTTHEWI. Huitt (-^p.), Vllf. PRIMA, jNIiltliu'W. 

 Fig. 25. The extei-ior of the pedicle-valve ; showing the character of the surface ornamentation. X 3. 



ACKOTIIELE ]\IaTT1IE\VI. HiUtt, V;ir. LATA, MattllL'W. 



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

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

 Pig. 28. Pi-ofile of the latter. X 3. ' 



St. John group. Haiifvrd Brook, New Brunswick. 



Acrothele Matthewi, Hartt (sp.). 



Fig. 29. The interior of a brachial valve ; showing the median septitni and adjacent muscular scars. X 3. 

 St. John gi'oup. Portland, New Brunswick. 

 Figs. 25 to 29 are from the original specimens figured by Jir. Matthew. 



Acrothele subsidua. White. 



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

 Fig. 31. The interior of the brachial valve with a faint median sejitum. X 2. 

 Middle Cambi-ian. Antelope Spri7igs, Utah. 



