EXPLANATION OF PLATE I. 
CREPICEPHALUS (LOGANELLUS) MONTANENSIS. 
Fig. 1. View of the glabella and fixed cheeks partly restored in outline..---..----------+----22 eee ee ee eee eee 
Fig. 2. Profile of the same, showing the elevation of the middle portion 
ARIONELLUS TRIPUNCTATUS. 
Fig. 3. View of the glabella and fixed cheeks, showing the form and surface-markings...--..----.--------.---- 
Figs. 4 and 5. Left and right movable cheeks of the species......---..-+ seb Ge aiteidcaveaiaiacin e ciweieicraereSiSie, sociated 
Pinna LuDLovi. 
Fig. 6. View of the right side of the specimen described, showing the radii, with their characteristic duplica- 
MYALINA (GERVILLIA) PERPLANA. 
Fig. 8. View of the specimen, with the basal portion restored, according to the lines of growth 
GRYPHEA PLANOCONVEXA. 
Fig. 9. View of a lower valve, retaining a portion of the shell and showing the beak. The lower part of the 
specimen is wholly an internal cast, and shows the form and position of the muscular impression...... 
Fig. 10. View of the under surface of the specimen as seen when separated from the shell of the smaller valve, 
showing the cartilage-area of the lower valve and the muscular imprint of the smaller one 
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