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6i 



TERTIARY FAUNA OF FLORIDA 



they merge into one another through their peripheral species. Such are the 

 following : 



Group of A. barbata L. {Barbatin s. s.). This includes A. (Z?.) mississippicnsis 

 Conrad from the Vicksburgian Oligocene. 



Group of A. Candida Gmelin (Calloarca Gray, 1857, + Plagiarca Conrad, 

 1875).* This includes A. aicidloidcs Conrad (+ A. lima Conrad, 1S47, 

 not of Reeve, 1844, = A. Conradi Desh.) from the Jacksonian ; A. mary- 

 la7idica Conrad and A. arcida Heilprin, Upper Oligocene and Older Mio- 

 cene ; and several other species. Liiharca {lithodomus) Gray, 1840, is 

 probably based on a specimen of A. Candida, which had grown in the 

 burrow of a Lithodounis. Upper Cretaceous to recent. 



Group of A. propatula Conrad (Granoarca Conrad, 1862) = A. hians Tuomey 

 and Holmes, 1855, not of Brown, 1842; nor of Reeve (? ^ A. protracta 

 Rogers, 1837, not of Conrad, 1847). Miocene. 



Group of A. ccntenaria Say (Striarca Conrad, 1862). Miocene. 



Group of A. donacifornns Reeve (Acar Gray, 1847, + Daphnoderma Morch, 

 1853, + Fossidarca 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 ty^xcsS. Acar the 

 lozenge is obliquely directed backward, leaving the anterior part of the area 

 bare ; in Fossidarca the lozenge is small, very short, and directly between the 

 beaks, leaving a bare space before and behind it. A. ccBlata Conrad (A. Adamsi 

 Shuttleworth) is a typical Fossidarca. 



Group o{ A. heterodonta Desh. {Les Cucidlaires Desh., i860; Cncullaria Conrad, 

 1869, + Nemodon Conrad, 1869). Cretaceous (Ripley) to recent. 

 In the Barbatias as well as in Glycymeris {Pectiinculus 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 Citcullaria the latter are almost, if not quite, 



* Plagiarca is based on Barbatia carolinensis Conrad, 1875 (Ripley beds of North Carolina), 

 not Area carolinensis Wagner, 1847, nor A. (Noetia) carolinensis Conrad of 1862. Polynema Conrad 

 (Kerr. Geol. Rep. N. Car., 1875, App. A., p. 4), based on Barbatia lintea Conrad, 1875 (not Area 

 lintea Conrad, Dead Sea Expedition, 1852), does not appear to differ from Plagiarca or Calloarca in 

 any characters of importance. The name Polynema is, at any rate, preoccupied in Entomology since 

 1833.* Navicula aspersa Conrad and Barbatia aspersa Conrad, 1S55 (not of Philippi, 1836), are 

 synonymes of A. cuculloides. 



