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SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 85 



Identifications of Mollusca — Continued 



Land shells 



Family 

 Buliinulidae . 

 Urocoptidae 



Pupidae 



Achanitidae . 

 Glandinidae . 

 TestacelHdae 

 Circinariidae 

 Zonitidae . . . . 

 Limacidae . . . 

 Arionidae . . . 

 Philomycidae 

 Endodontidae 

 Succineidae . 

 Vaginulidae . 



Percentage of 

 identifications 



The outstanding impression given by the foregoing table is that 

 notwithstanding their relatively low availability to birds, mollusks of 

 practically all kinds are eaten. In general it is also true that the large 

 groups more numerous in species and individuals contribute most 

 heavily to avian subsistence, while the small groups of less abundance 

 get ofif with a light toll. 



Let us see what are the relations of birds to some of the protected 

 mollusks. In a paper " On the Adaptive Coloration of Mollusca " 

 (Proc. Boston Soc. Nat. Hist., vol. 14, pp. 141-145 (1871) 1872), 

 Edward S. Morse alludes to protective coloration of several species. 

 His remarks with comment deduced from our tabulations are here- 

 with presented. "Among the marine forms we notice the adaptive 

 coloration of certain species very well marked. The common IJttorina 

 of the coast swarms on the bladder weed, the bulbous portions of 

 which are olive 1)rown in color or yellowish according to age. The 

 shells of the Litforiiia found upon it, present in their varieties these 

 two colors and are limited to these colors " ( p. 143). Our taliulations 

 show 503 records of capture of Littorina, 11 species of which were 

 identified from the stomachs of 46 kinds of birds. These shells are 

 freely eaten as the following instances of large numbers taken by 

 single birds testify : Pacific eider no, surf scoter 120, black duck 150. 

 purple sandpiper 205, and greater scaup duck 350. 



