ORTMANN: monograph of the naiades of PENNSYLVANIA. 41 



Epidermis yellowish to brownish, when young with indistinct rays, and the green 

 color of the rays often spreads out over the shell in indistinct transverse bands or 

 patches (under the larger nodules), so that the whole surface often appears more 

 or less suffused with green. But there are never triangular spots (as in Q. melanevra 

 and Q. cylindrica) . Growth-rests more or less distinct, brownish. Old shells 

 often are uniforml}- brown, and the sculpture disappears toward the lower margin. 

 Hinge-teeth moderately strong. Pseudocardinals divergent, ragged; inter- 

 dentum moderately developed. Beak-cavity moderately deep. Dorsal muscle- 

 scars on hinge-plate. Nacre white. No differences between the male and female 

 shell. 



L. H. D. 



5t2e; 1. Cooks Ferry, Cat. No. 61.3869 72 mm. 60 mm. 36 mm. 



2. Erie, Cat. No. 61.4526 64 " 52 " 29 " 



This species gTow^s considerably larger outside of Pennsylvania. 



Soft parts: Ortmann (1912, p. 253). Glochidia, figured by Surber (1915, p. 8, 

 pi. 1, fig. 11), remarkably small (0.085 X 0.090 mm.), much resembling those of 

 Q. verrucosa. Howard (1914, pi. 5, fig. 29) also gives a figure. 



Breeding season: Wilson & Clark (1912a, p. 43) report this species as found 

 beginning to become gravid on August 21 in Illmois, and Surber found specimens 

 with glochidia in August in Kansas. 



Remarks: The broad, smooth furrow of the disk and the sculpture distinguish 

 this species sufficiently from all other Pcnnsylvanian forms. The sculpture is 

 very variable, sometimes rather slightly developed, in other cases strong and very 

 prominent. Only a few specimens having been found in our state, no important 

 variations arc to be noted. The color-pattern of this species, although quite 

 variable, is characteristic in so far that the rays never break up into well-defined 

 spots. 



Localities in Pennsylvania, represented in the Carnegie Museum: 



Ohio River, Cooks Ferry, Beaver Co. 

 Lake Erie, Presque Isle Bay, Erie, Erie Co. 



Other localities represented in the Carnegie Museum : 



Miami-Erie Canal, Lucas Co., Oliio (C. Goodrich). 



Oliio River, St. Marys, Pleasants Co., West Virginia; Parkersburg, Wood Co., West Virginia; Ports- 

 mouth, Scioto Co., Ohio. 

 Middle Island Creek, Union Mills, Pleasants Co., West Virginia. 

 Wolfe Creek, Wolfe P. O., Washington Co., Ohio (W. F. Graham). 

 West Fork White River, Riverside, Greene Co., Indiana (J. D. Hasenian). 

 Wabash River, New Harmony, Posey Co., Indiana (A. A. Hinkley). 



