1387 



Pleistocene of Simmons Bluff, South Carolina ; recent from North Caro- 

 lina to the West Indies and San Sebastian, Brazil, in two to six hundred and 

 forty fathoms. 



This, the latest member of the series, is also the most elegant, the lamella- 

 tions on the dorsal area being more prominent and numerous than in any of 

 the others, the shell flatter, the concentric sculpture more regular, and the 

 radial basal striation more extensive. P. cancellaris Philippi is the corre- 

 sponding Pacific coast species, but it has not yet been reported in a fossil state. 



Genus DIVAHIOELLA von Martens. 



Divaricella von Martens, Beitr. z. Meeresf. Mauritius und Seychellen, p. 321, 1880, sole ex. 

 L. angulifera von Martens, loc. cit., pi. xxii., fig. 14; Lucina ornata Reeve, 1850; not 

 of C. B. Adams, 1852. 



Cyclas Moerch (as of Klein), Cat. Yoldi, ii., p. 32, 1853 (not of Lam, 1799) ; first sp. 

 C. quadrisulcata Orbigny, Conrad, Proc. Acad. Nat. Sci., vii., p. 30, 1856; H. and A. 

 Adams, Gen. Rec. Moll., ii., p. 467, 1857; Stoliczka, Paleont. Indica, Pelecypoda, p. 

 252, 1870; Cossmann, Catal. Illustr., ii., p. 45, 1887. 



Egraca (sp.) Leach, Moll. Gt. Brit., p. 310, 1852 (L. divaricata). 



Strigilla (sp.) Turton, Dithyra Brit., p. 117, 1822; Gray, List of Brit. An., p. 98, 1851 

 (Tellina divaricata L.). 



Strigella Gray, P. Z. S., 1847, p. 195 ; err. typ. pro Strigilla. 



>Lucinella Monterosato, Nat. Sicil., p. 91, 1883; Nomencl. Med., p. 18, 1884; sole ex. 

 Lucina commutata Philippi, Mol. Sicil., L, p. 32, pi. Hi-, fig- 15, 1836, = Tellina divari- 

 cata Linne, Syst. Nat., ed. x., p. 677, 1758; + Cardium arcuatum Montagu, Test. Brit., 

 p. 85, pi. iii., fig. 2, 1803; + C. discors de Gerville (non Montagu), Cat. Coq. Manche, 

 p. 18, 1825 ; -f- Tellina digitaria O. G. Costa (non Linne), Cat. List, pp. 14, 22, 1829; 

 not Lucina divaricata of authors. 



Lucina (sp.). of many authors, 1818-1880. 



Loripes (sp.) S. Wood, Ann. Mag. Nat. Hist., vi., Nov., 1840, p. 248; Crag. Moll., ii., p. 

 137, 1853. 

 This group presents many of the characters of Lucina proper, but is well 



distinguished by its extremely characteristic sculpture. There are several 



recent species requiring close examination to discriminate. Nearly all these, 



together with most of the Tertiary species, were lumped together by early 



writers under the name of Lucina divaricata. The hinge when fully developed 



has the following formula: L - IQ>- "*>'. The laterals are variable, especially the 



R. olo.oioi.l . . 



posterior laterals, which in some species are obsolete ; the anterior laterals ar< 

 more persistent, though usually feeble, and are situated near the cardinals at 

 the anterior end of the lunule. The anterior and posterior dorsal areas are 



