PLATE 99. 
Page 
425 
Fig. 1 - 10. SriRIFER ALIENOSUS. 
1, 2 & 3. Casts of the dorsal valve of young and medium-sized specimens. 
4 & 5. Casts of larger individuals, showing the marks of the muscular impressions. 
6 a. A specimen below the medium size, in which the marks of the muscular impression are 
well preserved, the transverse striae being as distinct as in older shells. 
6 b. Cardinal view of the same specimen. 
7 & 8. Casts of the ventral valve of very old specimens. 
§ &, 10. Casts of the dorsal valve, the latter figure presenting an unusual extension of the beak. 
