MUSSELS OF CUMBERLAND EIVER AND TRIBUTARIES. 55 



46. Lastena lata (Rafinesqiie). 



Very few examples seen in addition to those enumerated in the table. Mr. Boepple 

 obtained it at Bumside, Albany Landing, and Cloyds, Its apparent scarcity is due 

 in part to its habits. It can not be caught on the crowfoot hook, but must be obtained 

 by wading, and is best secured when the water is low and clear. The species appears 

 to prefer gravel bars with a rather swift current. The shell is beautifully polished 

 and rayed, and is very thin, cracking easily when exposed to the air. Our examples 

 are rather badly eroded. 



47. Anodontoides ferussacianus (Lea). 



Rare; only a few specimens found. A thin, fragile Anodonta-like shell of no com- 

 mercial value. 



48. Pegias fahula (Lea). 



A rare species of which we found only two living and four dead specimens in the 

 Rock Castle River near Livingston, Ky. They are quite small, the smallest measur- 

 ing 22.7 mm. long, 15.5 mm. high, and 11 mm. in diameter, and the largest 31 mm. 

 long, 20 mm. high, and 14 mm. in diameter. In their perfect condition these must 

 be very attractive little shells, but our specimens are very badly eroded. 



49. Symphynota costata (Rafinesque). Fluted shell. 



Occasional in the upper Cumberland from the falls down to the foot of Gowers 

 Island. Occurs typically in moderately small streams and appears to be entirely 

 absent from the lower stretches of the Cumberland. It is rather common in the 

 various tributaries. The Stones River shells were exceptionally thick and heavy, 

 and bore a goodly number of dead or soft pearls. 



On account of its yellow nacre and tendency to crack this species is of no use in the 

 manufacture of buttons. 



Several of our specimens have numerous deep wrinkles extending ventrally over 

 the posterior half of the disk. One is unusually shortened, truncate posteriorly and 

 produced forward, and has well-marked rays, while another medium-sized shell from 

 a mile below the falls is unusually elongate. 



50. Symphynota complanata (Barnes). White heel-splitter. 



Rare; only two examples of this species were found in the entire Cumberland. 

 The shells were small, thin, and badly stained. These were obtained on Red Rock 

 bar below Clarksville. Fragments of large strong shells were found in the Harpeth 

 River. This species thrives in a muddy bottom and is often found in sloughs. Under 

 especially favorable conditions it produces a fairly thick large shell which furnishes 

 usable button material, but the Cumberland shells of this species have no value. 



51. Alasmidonta minor Lea. 



Confined to the upper river and tributaries. So far as our experience goes, this 

 species is found typically in small streams, living in the sand between rocks. It may 

 live along the border of large streams, but on account of its small size would be easily 

 overlooked. Most of the specimens found had been killed by muskrats. The shells 

 were all badly eroded and so deeply stained that the characteristic rays were ob- 

 scured and the nacre rather badly stained. 



This species is always too small to have any commercial value. Our smallest 

 example measures 17 mm. long, 11 mm. wide, and 6 mm. in diameter, and our largest 

 45 mm. long, 28 mm. wide, and 18 mm. in diameter. 



This species closely resembles A. calceola, a better known and more widely dis- 

 tributed species, but has a heavier shell and teeth and darker epidermis, and is some- 

 what flatter and longer. 



