LIST OF CONTRIBUTORS. 85 



Lea, Isaac. Continual. 



On the visual organs of Unio. P '57, 17 



Description of thirteen new species of unios from Georgia. 



P '57, 31 



Description of six new species of Uniones from Alabama. 



P '57, 83 



— Description of eight new species of Naiades from various parts 

 of the United States. P '57, 84 



— Description of twelve new species of Naiades from North 

 Carolina. P '57, 85 



— Description of three new exotic species of Naiades. P '57, 85 

 Description of six new species of fresh water and land shells 



of Texas and Tamaulipas, from the collection of the Smith- 

 sonian Institution. P '57, 101 



— On specimens from the Red Sandstone of Phoenixville, Pa. 

 P '57, 149 



- — Descriptions of twenty-seven new species of Uniones from 



Georgia. P '57, 169 



— On the Red Sandstone of Gwynedd. P '57, 173 



— On chrysatolite. P '57, 173 



— ■ On trilobites from Braintree, Mass, P '57, 205 



— On conglomerate from Blossburg Mountain. P '58, 11 

 — ■ On fresh water Mollusca from Nebraska, etc. P '58, 13 



— On rosin from Borneo. P '58, 15 



— Descriptions of new species of Unio, from Tennessee, Ala- 

 bama and North Carolina. P '58, 40 



— Descriptions of a new Helix and two new Planorbes. P 



'58, 41 

 — On Permian and Triassic formations in Kansas and Penn- 



sylvania. P '58, 90 



— Remarks on Unionidas. P '58, 114 



— ■ Description of four new fresh water molluscs from the 

 Isthmus of Darien and Honduras. P '58, 118 

 - — On Unio rubiginosa. P '58, 135 



— Descriptions of seven new species of Margaritana and four 



new species of Anodontae. P '58, 138 



— Descriptions of twelve new species of Uniones and other fresh- 

 water shells of the United States. P '58, 165 



— On Tricnietra contorta. P '58, 179 



— On fossils from Haddonfield, N. J. P '58, 218 



— Description of eight new species of Unionidae from Georgia, 



Mississippi and Texas. P '59, 112 



