1 86 Bryant Walker 



Truncilla brevidens (Lea). 



Vanatta (140, p. 550) states that the shell in the Poulsoii collection la- 

 belled Ohliquaria interriipta Raf. is this species. If identifiable from the 

 original description, Rafinesque's name has precedence. 



Truncieea perpeExa (Lea). 



This species has been identified by Conrad and others as Arnblema toru- 

 losa Raf. and Amhlema gibbosa Raf. According to Vanatta (140, p. 550) 

 the shells so labelled in the Poulson collection are this species. Either 

 name, if identifiable from the original description, would have priority. 



Truncieea s^jlcata (Lea). 



Unio stewardsoni stevensoni De Gregorio, Moll, di aq. dul. di Amer., 1914. 

 p. 15, pi. VI, fig. 3. 



Unio propesidcatus De Gregorio, Ibid, p. 30, pi. X, fig. 2. 



Vanatta (140, p. 550) states that the shell in the Poulson Collection 

 under the name of Obliquaria obliquata Raf. is this species. If identifiable 

 from the original description, it would take precedence. 



Trunciela triquETra Rafinesque. 



Unio triangularis pergibbosa De Gregorio, Moll, di aq. dul. di Amer., 19T4, 



p. 10, pi. II, fig. 4. 

 Unio triangidaris longiuscidus De Gregorio, Ibid, p. 10, pi. TI, fig- 5- 



Truncilla TRIQUETRA TRIANGULARIS (Barnes). 



Barnes' types of his Unio triangidaris came from Bois Blanc Island in 

 the Detroit River and the form is fairly entitled to varietal rank, being like 

 nearly all of the UnionidcB of the Great Lakes a characteristically depauper- 

 ate race. 



Truncieea walkeri Wilson and Clark. 



Truncilla zvalkeri Wilson and Clark, Bur. of Fish. Doc, No. 7S1, IQ14, p. 



46, pi. I, fig. I. 

 Type locality : East Fork of Stone's River, Walterville, Tenn. 



Subgenus DYSNOMIA Agassiz, 1852. 



Frierson (42, p. 7) identifies Rafinesque's Unio or Bpioblasma biloba 

 with 7\ foliata (Hild.) and consequently replaces Agassiz' subgeneric name 

 by Bpioblasma Raf. 



