igo6] A Visit to Duck Island. 187 



A VISIT TO DUCK ISLAND. 



The glorious sun of a September afternoon shone warmly on 

 a group of club members who recently visited Duck Island, the 

 metropolis in the vicinity of Ottawa of the elusive unionidae, 

 vulgarity called clams. The weather was delightful. The water 

 was very low and unruffled and collecting was consequently easy 

 and rapid. The many sand bars which project from the centre of 

 the iland towards Templeton wharf yielded the first fruits in fine 

 specimens of Unto occldens and Unto borealis. A little lower 

 U complanatus was fouud in abundance. Few however of the 

 specimens were of the very large, rayed form, for which the local- 

 ity is particularly noted. But certain of the shells procured quite 

 equalled the first found in 1881, which for a quarter of a century 

 have increased in loveliness, and form the chief glories of the 

 writer's cabinet. The heavy, inflated, unrayed form of complana- 

 tus, not occurring elsewhere than at the island, was very numer- 

 ous, and some fine shells were selected from the thousands whose 

 circular tracks furrowed the sand in every direction, always how- 

 ever with an uultimate trend to deep water. U. ellipsis, of small 

 size was oommon, but there were few mature shells. This species 

 is known in the Western States as "the nigger toe-nail", and is 

 much used in the pearl button industry. Another shell of econo- 

 mic use, which occurred sparsely, is U. rectus, called by pearlers 

 the "black sand-shell." 



U. gibbosus was not uncommon, but not one afforded a mate 

 for the fine pearl found six years ago in a shell of this species 

 collected at the foot of the island. Several large U. gracilis were 

 noticed, and a few shells of medium size saved. Of our only 

 other winged shell, U. alatus, a single fine specimen was obtained. 

 U. alatus and U. rectus are remarkable among North American 

 unios for their extensive range Quebec to Manitoba, and south- 

 ward far into the Mississippi Valley and for their constancy of 

 form, under the widely differing conditions of their environments. 

 A tew specimens of Anodonta undulata were found, and a single 

 fine A. BenedictiL the third living shell noted in more than 

 twenty years. The others were found at the mouth of Brigham's 

 Creek. Of the Margaritanas but one was noticed M. uftdulata. 



