Catalogue Reccnti^y Described Mollusca 165 



Class LAAIELLIBRAXCHIA. 



Order EULAMELLIBRAXCHIA. 



Suborder SUB.AIYTILACEA. 



Family AIARGARITAXID.E. 



Ortmann (79, p. 223) has raised the genus Margarltana to the rank of 

 a family and (80, p. 13) has proposed a new genus, Cumberlandia, for M. 

 monodonta (Say), both based upon anatomical peculiarities 



For the distribution of the genus in this country, see Walker, Xos. 152 

 and 153, Ortmann (80, p. 14) and Utterback (135, p. 99). 



Margaritana margaritifera (L.)- 



Unio ocmulgccnsis doiiiiiiiis De Gregorio, AIoll. di aq. dul. di Amer., 1914, 

 p. 13, pi. 7, fig. a-c. 



Family UNION ID.f:. 



Simpson's "Descriptive Catalogue of the Naiades'' brings the subject 

 down to January i, 1913. 



For the revised classification so far as it has progressed, see Part I. 



In view of the relatively small number of species that have been exam- 

 ined anatomically and the consequent element of uncertainty as to the sys- 

 tematic position of the remainder that must continue until the animals can 

 be critically examined, it has seemed better, for convenience of reference, 

 in this porton of the work to retain the generic names given 'by Simpson, 

 noting, however, under such species as have been examined anatomically 

 their proper place in the revised classification. 



Recent attempts to revive Rafinesque's names for many of the species 

 have created considerable confusion as to the proper nomenclature to be 

 followed. 



Vanatta's valuable paper on '"Rafinesque's Types of Unio" (140, p. 549), 

 reviewed by Walker (158, p. 43), has given definite information as to what 

 Rafinesque in 1831 understood or claimed to be the species that he had 

 described in 1820. 



It has been too hastily assumed by some that these determinations have 

 definitely settled the validity of all of the Rafinesqueian species involved. 

 This is far from correct. It is not claimed, except in one instance, that the 

 so-called types in the Poulson collection are the original types of Rafinesque. 

 And, even if they were, reference to them for the purpose of determining 

 an otherwise unidentifiable description is prohibited by the International 

 Code (Op. Int. Co., I). The requisites for a sufficient description are defi- 

 nitely specified by the Code (Art. 25) and these provisions as defined by 

 the decisions of the International Committee must be applied to each indi- 

 vidual case. 



