1903] 



CONCHOLOGY, 



305 



aging 57f cc, point to the probability of a new female, and 

 indeed it is not likely that any red-shouldered hawk lives as long 

 as 13 years in a country so thoroughly hunted as that about Lon- 

 don. In 1899, this pair provided a surprise, for, from the same 

 nest in the same beech tree was taken set No. 4165 which, while 

 averaging 55^ cc, only 2^ cc. different from those of 1898, 

 differ remarkably in shape, being long like a hen's egg ; yet the 

 colors approximate closely to those of the 1899 eggs, and they 

 were probably laid by the same hen. In 1900 a sugar camp was 

 located beneath this tree and the nest of these hawks was not 

 found. In 1901, however, a pair was on the scene once more 

 with a nest in a maple less than 100 yards from the old nest, and 

 this time set No. 3777 was taken, consisting of 4 normally shaped 

 eggs averaging 51^ cc. and resembling less closely those of the 

 former years. In 1902, from another maple near the last, was 

 taken set No 3882, averaging 52^ cc, which bear no resem- 

 blance to those of former years either in color or shape. 



CONCHOLOGY. 



Niagara River Shells. 



Dr. James Fletcher was recently at Niagara Falls, and taking 

 advantage of the conditions resulting from the construction of a 

 wing-dam above the Dufferin Islands, by which a large portion of 

 the river bed above the falls has been laid bare, he collected quite 

 an interesting series of shells. 



The following species have been noted : 



Linnsea catascopium, Say. 

 Goniobasis livescens, Menke. 

 Pleurocera subulare. Lea. 

 Unio luteolus, Lamarck. 

 U. ellipsis. Lea. 

 U. gibbosus, Barnes. 

 Margaritana marginata, Say. 

 Sphaerium striatinum, Lamarck. 



