TRANSACTIONS OF WAGNER 

 908 



TERTIARY FAUNA OF FLORIDA 



growth that the fossil species may be distinguished from the Mactras rather 

 than by any clearly marked differential characters. 



The nomenclature of the genera comprised in this family has always 

 been more or less confused. In 1799 Lamarck proposed a genus Papilla, 

 without naming any type. The diagnosis comprised no characters which 

 would differentiate the genus from Mactra. Moreover, the name had been 

 proposed for a group of Vencridce during the previous year by Bolten. In 

 1801 Lamarck repeated his diagnosis, and cites as examples a small, short 

 species of Crassatella and Papliia glabrata Lam. (not Mactra glabrata [L.] 

 Gmelin). The latter of the two has commonly been regarded as the type of 

 Paphia, the Crassatella being referred to its own genus. Subsequently, La- 

 rtiarck abandoned the genus Paphia and referred P. glabrata to the genus 

 Crassatella without remark (An. s. Vert., 5, p. 482, Ann. du Mus., 6, p. 408). 

 The name Paphia being preoccupied, another name is necessary. Sowerby 

 had referred species of this type to Erycina Lam. (though they were not the 

 typical Erycina), and Swainson, on the ground that Erycina was preoccupied 

 by Fabricius, proposed Eryx in 1840 for the group of which P. glabrata is 

 the type. This name, also, is unfortunately preoccupied in entomology. 



In 1812 Lamarck used the name Donacillc for a shell described by Poli 

 under the name of Mactra cornea. But, as printed, Donacille was a vernacular 

 nomen nudum, without diagnosis or type, and, in 1818, Lamarck described 

 a genus Amphidesma, in which he combined much heterogeneous material, 

 including his earlier Donacille, which he states is synonymous with Ainplii- 

 desma and had been based on Poli's Mactra cornea. In 1830 Lesson pro- 

 posed for the Mya novcezelandice of Chemnitz the name of Paphics (Du- 

 perrey, Voy. Aut. du Monde, ii., p. 424) to indicate the affinity which it seemed 

 to show to the suppressed Paphia of Lamarck. In the same year Dcshayes 

 brought together, under the name of Mcsodcsma, Lamarck's Paphia, some of 

 Lamarck's Crassatellas, Amphidesmas, and his uncharacterized Donacillc, but 

 without naming a type. His first species was M. donacia, a large Chilian 

 form. The species from which he obtained the anatomical data, mentioned in 

 his diagnosis under the name of Mesodcsma Quoyi, does not appear to have 

 been described under that name, but was one of the large donaciform species 

 of New Zealand, perhaps M. ventricosa Gray. I have not found any positive 

 identification of it, and it is not in Deshayes's own manuscript list of Meso- 

 desmas in my possession. M. novcezelandiie Chemnitz is the second species 

 of Deshayes, and is not mentioned as the type, as mistakenly stated by Herr- 



