LIST OF CONTRIBUTORS. 175 



Troost, Gerard. Description of a new crystalline form of quartz. 

 j ii. 212 



Description of .some crystals of sulphate of strontian, from 



Lake Erie. J ii, 300 



Account of the pyroxene of the United States and descrip- 

 tions of some new varieties of its crystalline forms, j Hi, 105 



■ Notice of the yenite of Rhode Island, and several other 



American minerals, j iii, 222 



— Description of the American petalite from Lake Ontario. 

 j iii, 234 



— Description of a new crystalline form of the chrysoberyl. 



j iii, 293 



— Description of a new crystalline form of the andalusite. 

 j iv, 122 



— Observations on the zinc ores of Franklin and Sterling, 



Sussex County, New Jersey, j iv, 220 



Description of a new crystalline form of apophyllite, lau- 



monite, and amphibole, and of a variety of pearlstone. j v, 51 

 Trotter, Spencer. On Helminthophaga leueobronchialis (Brews- 

 ter) . P 77, 292 



Effect of environment in the modification of the bill and 



tail of birds. P '91, 118 



Trudeau, J. Description of the white winged tanager (Pyranga 

 leucoptera). j viii, 160 



True, Frederick W. A note on the common bottle-nosed por- 

 poise of the North Atlantic, Tursiops truncatus Montagu. P 

 '03, 313 



Remarks on the fossil cetacean Rhabdosteus latiradix Cope. 



P '08, 24 



Tryon, George W., Jr. On the Mollusca of Harper's Ferry, 

 Virginia. P '61, 396 



Synopsis of the recent species of Gastrochenidae, a family 



of acephalous Mollusca. P '61, 465 



On the classification and synonymy of the recent species of ' 



Pholadida?. P '62, 191 



Description of a new genus and species of Pholadida?. P 



'62, 449 



Notes on American fresh-water shells, with descriptions of 



two species. P '62, 451 



Monograph of the family Teredidse. P '62, 453 



Contributions towards a monography of the order of Pho- 



ladacea, with description of new species. No. 2. P '63, 143 



