PLATE XXXIV. 



PAGE 



Fig. 103. Osthea Idriaensis. Natural size. 203 



103 a. Hinge of lower valve from a very large specimen. 



Fig. 104. Ostrea aitressa. Natural size. 203 



101 a. Hinge. 



Fig. 105. PiHyxciionella "Whitneyi. Natural size. 204 



105 a. Side view. 



105 b. Outline of tlie libs. 



Fig. lot). i Smilotkochus cuktus. Top view. 205 



100 ft. Longitudinal section. 



