ORTMANN: monograph of the naiades of PENNSYLVANIA. 297 



St. Lawrence to Ottawa and Montreal (Bell, 1859; Simpson, 1891; iMarshall, 

 1895). 



Possibly it extends its range westward from the lower St. LawTence, for it 

 has been reported from Lake Nipissing (BeU, 1859), and even farther West, from 

 Lake Superior, Lake Winnipeg, and Nelson River, but these latter locahties require 

 confirmation, and a few additional records from Ohio and Indiana are certainly 

 wrong. Its presence in Michigan is doubtful (Walker, 1898). But it is positively 

 present in the region of Georgian Bay: specimens in the Carnegie Museum are 

 nearly nonnal, except that the color is often more bro^^^lish. 



This is an Atlantic species, belonging to the northern element in the Atlantic 

 fauna (Ortmann, 1913a). In New York it has crossed over into the lower St. 

 Lawrence-drainage, and apparently has here a tendency to spread westward 

 along a route, which lies North of Lake Erie. If this shovdd prove to be correct, 

 attention should be called to the similarity of this range with that of Elliptio 

 violaceus. 



In New York its range in part overlaps that of L. luteola (certainly in the 

 Mohawk and St. Lawrence drainages), but particulars as to the mutual relation 

 and possible association of these two species are lacking. This is a question which 

 requires closer investigation. 



As far as known, this species prefers tidewaters, but ascends some of the 

 larger rivers to a considerable distance (Hudson, Susquehanna). Nevertheless in 

 the south it apparently does not have this tendency. The fact that it often goes 

 into canals and is frequently found in lakes, also indicates that rough water and 

 rough bottom (riffles) are not very favorable to it. 



Lampsilis ovata (Say) (1817). i" 

 Lampsilis ovatus Simpson, 1914, p. 48. 



Plate XVII, figs. 8, 9;. Plate XVIII, figs. 1, 2, 3. 

 Records frotn Pennsylvania: 



Call, 1885 (Alleghenj' River, up to central New York). 



Clapp, 1895 (Allegheny Co.). 



Marshall, 1895 (Allegheny River, Warren, Warren Co.). 



Rhoads, 1899 (confused with L. ovata ventricosa, but specimens from Oliio River, Coraopolis, Allegheny 



Co., and Beaver, Beaver Co., belong here). 

 Ortmann, 19096, p. 189. 



Characters of the shell: For reasons given below, it is best to describe this 

 form in terms of comparison with its variety, L. ovata ventricosa (See remarks). 



"' Not 1816. 



