1 78 Bryant Wai^ker 



Genus ALASMIDONTA Say, 1818. 

 Subgenus PRESSODONTA Simpson, 1900. 



I have recently (162, p. 2) proposed to supercede this name with that 

 of Calceola Sw., 1840, on the ground of priority. Dr. Dall has since called 

 my attention to the fact that Calceola had already been used by Lamarck 

 in 1799 for a coral. Simpson's name will therefore stand. 



Subgenus PROLASMIDONTA Ortmann, 1914. 



Prolasmidonta Ortmann, Naut., XXVIII, 1914, p. 44. 

 Type: Unio Jieterodon Lea. 



Subgenus PEGIAS Simpson, 1900. 



According to Ortmann (81, p. 45) this group is a subgenus of Alasmi- 

 donta. 



Subgenus RUGIFERA Simpson, 1900. 



Alasmidonta marginata Say. 



Unio calceolus sciotincola De Gregorio, Moll, di aq. dul. di Amer., 1914, p. 

 24, pi. IX, fig. 3. 

 Frierson (42, p. 7) has identified Alasmodon scriptiim Raf. with this 

 species, but Say's name has priority. 



Ar^ASMiDONTA ravEne;i,iana (Lea). 



Frierson (42, p. 7) has identified Alasmodon atropnrp^ireum Raf. as be- 

 ing this species. If identifiable from the original description, it has priority. 



On the basis of these identifications, he would substitute Decuramhis 

 Raf., 183 1, for Rugifera Simp, as the subgeneric name. 



Genus SIMPSONICONCHA Frierson, 1914. 



Hemilastena Simpson, non Agassiz, Syn., 1900, p. 673; Desc. Cat., 1914, p. 



323- 



Simpsonaias Frierson, Naut., XXVIII, 1914, p. 7. (Preoccupied.) 

 Simpsoniconcha Frierson, Naut., XXVIII, 19 14, p. 40. 

 Type: Alasmodonta amhigua Say. 



For note on this name, see Walker, 162, p. 4. 



Subfamily LAMPSILIN^ Ortmann, 1912. 



Genus PTYCHOBRANCHUS Simpson. 



Frierson, having identified (42, p. 7) Obliquaria fasciolaris Raf. with 

 P. phaseolus (ITild.), has designated it as the type of BUipsaria Raf. and 

 gives the latter priority as the generic name. 



