550 PROCEEDINGS OF THE ACADEMY OF [NoV., 



Truncilla triquetra Raf. 



Truncilla triqueler (Unio triqueter) Raf. Monogr. (1820), p. 300, No. 18, 

 PI. 81, fig.s. 1, 2, 3, 4. 



The type is A. N. S. P. Coll. No. 20,231. 



Length 55, height 37, diam. 32.5 mm. 



This is Truncilla triquetra Raf. of Simps. Synopsis, p. 517, and 

 A Descriptive Catalogue of the Naiades by C. T. Simpson, Detroit 

 (1914), p. 5. 



Truncilla brevidens Lea. 



Obliquaria interrupta (U. do.) Raf. Monogr. (1820), p. 302, No. 21. 



The type is A. N. S. P. Coll.- No. 20,257, from the Ohio River. 



Length 55.5, height 43, diam. 26.5 mm. 



This is Truncilla brevidens Lea (1834) of Simps. Synopsis, p. 517, 

 and Descr. Catal., p. 7. It is preoccupied by Unio solenoides inter- 

 rupta Raf. (1820), p. 298, No. 13, var. 1. 



Truncilla obliqua Raf. 



Obliquaria obliquata {U. obliquata) Raf. Monogr. (1820), p. 309, No. 40. 



The type is A. N. S. P. Coll. No. 20,226, from the Kentucky River. 



Length 59, height 43, diam. 32.5 mm. 



This is Truncilla sulcata Lea (1830) of Simps. Synops., p. 520, 

 Descr. Catal., p. 14. It is the first name for the species. Unio 

 sulcatus Lea (1830) is preoccupied by Unio cuneata var. sulcata Raf. 

 Monogr. (1820), p. 313, No. 52, var. 2. 



Truncilla torulosa Raf. 



Amblcma torulosa {Unio torulosa) Raf. Monogr. (1820), p. 314, PL 82, figs. 

 11, 12. 



The types are A. N. S. P. Coll. No. 20,218. This is the figured 

 specimen. 



Length 65, height 48, diam. 33.5 mm. 



Tray No. 20,216 is another specimen from the Kentucky River. 



Length 66, height 58, diam. 36.5 mm. 



Amblemn gibbosa {Unio gibbosa) Raf. Monogr. (1820), p. 315, No. 56 (not 

 Barnes, 1823). 



The type is A. N. S. P. Coll. No. 20,232, from the Ohio River. 

 Length 40, height 33, diam. 25 mm. 



These shells are Truncilla perplexa Lea (1831) of Simps. Synops., 

 p. 522, Descr. Catal., p. 24. 



Truncilla flexuosa Raf. 



Obliquaria flexuosa {Unio flexuosa) Raf. Monogr. (1820), p. 306, No. 33. 

 The type is A. N. S. P. Coll. No. 20,249, from the Kentucky River. 

 Length 57, height 47, diam. 33 mm. 



