ORTMANN: monograph of the naiades of PENNSYLVANIA. 37 



Distribution and Ecology in Pennsylvania (See fi^. 5) : This is one of the rarer 

 species in Pennsylvania. It occurs in the Ohio and Monongahela, in the latter as 

 far up as the lower Cheat River, but it is missing in the headwaters of this system 

 in West Virginia. In the Allegheny River, it has been traced up into Armstrong 

 Co., and, in addition, it is found in the Beaver and Mahoning Rivers, but has 

 not been found in the Shenango. 



In all the other streams, not mentioned, it is absent, and thus its ecological 

 preferences are decidedly with the larger streams; but since it has not often been 

 found alive, details are scarce. I collected it myself in the heavy gravel of the 

 Ohio, Allegheny, and Cheat, as well as in coarse gravel in the Mahoning. On 

 similar bottom I found it in the Little Kanawha and Elk Rivers in West Virginia, 

 and in the upper Tennessee region. But in Pocatalico River I found it in pure 

 sand. In the Ohio in West Virginia and Ohio, it is abundant on the " shell banks," 

 in deep, strongly flowing water, with gravelly bottom, and here it is frequently 

 taken by the clam-diggers. Call (1900, p. 488) reports this species from muddy 

 bottoms as well as from sand and gravel bars. 



General distribution: Type-locality, Ohio (Lea). This species is quite char- 

 acteristic of the Ohio proper and its larger tributaries. It also belongs to the 

 Cumberland and Tennessee-drainages, and is there in its typical phase, but some 

 confusion exists as to this.^^ In the states of Ohio, Indiana, and Illinois it is a 

 common shell (Sterki, 1907a, Call, 1896a, and 1900, Baker, 1898a and 1906). 

 How far it extends West and Southwest is hard to say, but the typical form has 

 been figured by Scammon (1906) from Kansas. In this region, however, it is in 

 part represented by more or less distinct varieties. Among the material at hand, 

 there seem to be several of the latter, but I am well acquainted only with one (var. 

 schooler aftensis, see below) . 



Note: This species is only moderately swollen, or even rather flat, in Penn- 

 sylvania. Farther down the Ohio more distinctly swollen individuals are met 

 with, becoming sometimes almost globular, culminating finally in the type known 

 as dorfeuillana Lea (with high beaks). This indicates a tendency similar to that 

 observed in several of the preceding species, which, however, is in this case not so 

 distinctly marked, since Q. pustulosa does not go up, as a rule, into small streams. 



=1 The chiof mistake has been made by Simpson (1900, p. 780) in stating that the varieties pcrnodosa 

 Lea and kieneriana Lea (not keineriana ) are found in streams " draining into the Gulf of Mexico," 

 while the type-locality of pcrnodosa, at least, is in the upper Tennessee drainage. A singular double 

 mistake is made by Sterki (1907a, p. 391) in quoting " kleineriana " (for kieneriana) from Lake Erie. 



