594 ORTMANN—NAYADES OF 
are, as Simpson states, much like “Pleurobema appressus,” that is 
to say, Lexingtonia dolabelloides conradi (Van.). I have examined 
these in Washington. Also specimens in the Walker collection, la- 
beled abacus, from Flint River, Gurley, Madison Co., Ala., are this. 
MARGARITANA QUADRATA Lea (1861)—FEastern Tennessee. 
Symphynota quadrata Simpson, ’14, p. 487. 
The type is lost. This species never has been recognized. I 
have the suspicion, from description and figure, that it is identical 
with Alasmidonta minor (Lea), 1845. 
LIST OF LOCALITIES, AND OF THE NAYAD-FORMS 
FOUND AT THEM. 
The following list is submitted for two reasons: first, to give an 
idea of the richness of the material upon which this paper is founded ; 
second, to facilitate, for subsequent collectors, the search for cer- 
tain forms. There will be a time, not far distant, when the fauna 
of many of the localities will have deteriorated or disappeared in 
consequence of stream pollution, and thus it is important to know all 
the localities where a given form has been found. ‘The exact location 
of all the collecting stations is given on the accompanying map, so 
that also a change of local geographic nomenclature will not inter- 
ferew mee pace. 5235) 
The localities have been arranged according to river systems, be- 
ginning in the northwest (Powell), and proceeding downstream and 
eastward. The smaller streams not belonging to the headwaters, 
have been placed together at the end of each system. The Ten- 
nessee proper stands at the end of the list. 
Forms found intergrading at one locality are connected by 
braces. In several instances of well-known and easily recognized 
species, I have not taken home specimens at certain localities, but 
only seen them (mostly dead shells). These are marked “seen.” 
The record of this fact always was made in the field with actual 
specimens before me, and is absolutely reliable. 
