Occasional Papers of the Museum of Zoology 65 
Genus Dysnomra Agassiz, 1852 
Type: Unio foliatus Hild. = Obliquaria flexuosa Raf. 
Truncilla Rafinesque, ’20, p. 300 (no type named); Herrmannsen, 
"47, p. 627 (type, Truncilla truncata Raf.) ; Agassiz, ’52, p. 44 (no type 
named, first species, Tr. triqueter Raf.) ; Simpson, ’00, p. 516 (type, 
Tr. triqueter Raf.). 
Dysnomia Agassiz, '52, p. 43 (no type named, first species, Obli- 
quaria flexuosa Raf.) ; Simpson, ‘00, p. 521, as subgenus of Truncilla 
(type, U. foliatus Hild. = Obl. flexuosa Raf.). 
Since the type of Truncilla has been designated by Herr- 
mannsen as Tr. truncata Raf., this name takes the place of 
Amygdalonaias (which see). The next available name for 
this genus is Dysnonua Agassiz, the type of which has been 
fixed by Simpson. 
Subgenus TRUNCILLOPSIS n. n. 
Type: Truncilla triqueter Raf. 
Truncilla (subgenus) Simpson, ‘00, p. 517 (type, Truncilla triqueter 
Raf.). 
The removal of 7runcilla and the extension of the subgen- 
eric name Dysnomia to cover the whole: genus necessitates the 
introduction of a new subgeneric name for what was hitherto 
the subgenus Truncilla s. s. of Simpson. The name of Trun- 
cillopsis is therefore proposed. 
DysNoMIA (‘TRUNCILLOPSIS) TRIQUETRA (Rafinesque), 1820 
Type locality: Falls of the Ohio (at Louisville, Ky.). 
Truncilla triqueter Rafinesque, ’20, p. 300, pl. 81, f. 1-4. 
Unio triangularis Barnes, ’23, p. 272, pl. 13, f. 17. 
Unio cuneatus Swainson, Phil. Mag., ’23, p. 112. 
Unio formosus Lea, °31 (not ’34, as given by Simpson), p. 111, pl, 
TOM te Sus 
U. triqueter Raf. =U. triangularis Bar.=U. formosus Lea=U. 
cuneatus Sw., Conrad, ’34, p. 72; Ferussac, ’35, p. 27. 
Truncilla triquetra Raf., Simpson, ’14, p. 
-Truncilla triquetra Rat. Vanatta, “15, p: 
oat 
50 (“type” examined). 
cn 
