12 Palakontographica Americana 12 



Group of A. propti/u/a Convad {Granoarca Conrad; i862)r=,4. ///rtw^Tuomey and 

 Holmes, 1855, not of Brown, 1842; nor of Reeve (? — A. protrada Rogers, not of Conrad, 

 1S47). Miocene. 



Group of A. centenaria Say {Striarca Conrad, 1862). Miocene. 



Group of v4. donac!/ort}us'R.ee.\e{AcarGva.y, 1847,+Daphoderma Moerch, 1853, 

 -\-Fossularca Cossmann, 1887. Eocene to recent. 



"In Striarca the lozenge occupied by the ligament and its transverse grooves for 

 the resilium cover the entire cardinal area; in typical Acar the lozenge is obliquely di- 

 rected backward, leaving the anterior part of the area bare; in Fossularca the lozenge is 

 small, very short, and directly between the beaks, leaving a bare space before and be- 

 hind it. A. ceelata Conrad {A. .4(/(J/«^/ Shuttleworth) is a typical Fossularca. 



"Group of .4. hcterodonta Dssh. {Les Cucullaires Desh., i860: CiuuUaria Conrad, 

 i?,6g,-{-Ne7nodon Conrad, 1869). Cretaceous (Ripley) to recent. 



"In the Barbatias as well as in G'ycymeris {Peduncidus auct. ) the growth of the shell 

 often results in a greater or less absorption of the middle part of the series of teeth; the 

 distal teeth are always more or less oblique, especially those behind the beaks. In Cu- 

 cuUaria the latter are about, if not quite, parallel with the hinge-line. Consequently, it 

 may follow that in the process of growth the same individual may at an early stage 

 have a series of vertical median denticles, and at a later stage may present a hiatus des- 

 titute of teeth betwaen the anterior and posterior parts of the series. Judging from the 

 species I have been able to examine, the entire narrow cardinal area is originally cov- 

 ered by the ligament, but the grooves containing the resiliiun extend very obliquely 

 backward from the beaks, as in typical Acar. Notwithstanding the resemblance of the 

 hinge in these Tertiary and recent species to that of the Paleo'-oic and early Mezozoic 

 Parallelodon, I am of the opinion that the relations of the former are really closer with 

 the true Arks, and that the similarities will prove to be analogical rather than homo- 

 logous. The recent abyssal species I have formerly referred to Macrodon, should prob- 

 ably be grouped under Cuciillaria." — Dall, 189S. 



Area barbata Linne 

 Plate II, Figures 4, 5, 6, 7 



Area barbota Linn^, Syst. Nat., p. 693, 1758. 



"Peclitnciilus } fusco rufescens, adinodum densi slriatus" Lister, Hist. Couch., tab. 231, fig. 65, 



1 1 70. 

 Area barbata Gmelin, Syst. Nat., vol. 6, p. 3306, 1792. 

 Area borbola Reeve, Conch. Icon., pi. 13. Area no. 83, 1844. 



Barbatia barbata H. and A. Adams, Gen. Rec, Moll., vol. 2. p. 534, pi. 124, figs, 4, 4a, 4b, 1858. 

 Area barbata Arango, Fauna Malacologica Cubana, p. 263, 1S79. 

 Area (Barbatia) barbata Dall, U. S. Nat. Mus., Bull. 37, p. 40, 1889. 

 Barbatia barbata Dall, Wagner Free Inst., Sci , Trans., vol. 3, pt. 4, pp. 614, 615, 659, 1S9S. 



"A. testa oblonga striata apiicbus barbata, natibus incurvis approximatus, margine inte- 



gerrimo clauso. 



Mus. Tessin. 116. t. 6./. i, 



Bonan. recr. 2. t. yg. 



