130 UNITED STATES GEOLOGICAL SURVEY OF THE TERRITORIES. 



LUCINIDjE. 

 Genus LUCINA, Bruguiere. 



Synon.— Lucina, Brng. (1792), Encyc. Me"tb., tab. 284.— Lamarck (1801), Syst. An., 124 (uot 1799, = Loripcs, 



Poli, 1791).— Guvier (1817), Rogue An., 48-2 .- Lam. (1818), Hist., V, 538.— Feruss. 



(1821), Tab. Syst., xliii.— J. Sowerby, Mill. Couch., tab. 417.— Fleming (1828), Hist. 



Brit. An., 441.— Desb. (1830), Encyc. Moth., Ill, 371.— Agassiz (1839), Monl. de Moll., 



37.— H. and A. Adams (1857), II, 400 ; and of numerous later authors. 

 Trhloula (sp.), Sebum. (1817), Essai, 146.— Gray (1847), Proceed. Zoiil. Soc. Loud., 195 (as a sec. of 



Lucina). 

 LenHllaria, Sebum. (1817), Essai, 147. 

 Myriea (sp.). Turton (1822), Brit. Biv., 133.— Fleming (1828), Brit. An., 443.— Philippi (1 844), Mol. 



Sic., II, 2V— H. aud A. Adams (1857), Gen. Recent Moll., II, 408 (as a subgenus of 



Lucina). 

 Phacoides, Blaiuv. (1824), Diet. Sci. Nat, XXXII. 



Millhea, II. aud A. Adams (1857), Geu. Recent Moll., II, 408 (as a subgenus of Lucina). 

 * Cyelas, H. and A. Adams (1857), ib., 407 (as a subgenus of Lucina; not Cyelas, Brug.). 

 Here, Gabb (1869), Paheont. California, II, 28 (as a subgenus of Lucina). 



Eiym. — Lucina, a name of Juno. 

 Type. — Lucina Jamaieensis, Speugler. 



Shell more or less nearly circular, lenticular, or sometimes ventricose; 

 surface-characters variahle ; posterior dorsal slopes often with an oblique 

 sulcus; lunule generally well-defined, sometimes very deep; hinge usually 

 with two diverging cardinal, and two lateral teeth in each valve; lateral teeth 

 and one of the cardinals sometimes obsolete; ligament external, or some- 

 times rather deeply seated between the margins of the valves ; muscular 

 impressions well-defined, the anterior one being elongated within the well- 

 marked simple pallial line; interior surface within the pallial line more or 

 less rugose, and often having an oblique linear furrow in each valve. 



This genus includes the following subgeneric sections: 



1. lucina, Bruguiere (typical). 



Shell orbicular or more or less oval, moderately convex, concen- 

 trically striated or lamellate; cardinal and lateral teeth generally well- 

 developed. — (Type as already cited.) 



2. mtrtea, Turton. 



Shell ovate, rather compressed, concentrically striated, lamellated 

 or decussate ; hinge with lateral teeth, and one of the cardinals gen- 

 erally obsolete. — Lucina spinifera, Mont. 



* Klein used the name Cyelas, in 1753, for a group including divaricately-marked species of Lucina ; 

 but, for reasons stated farther on, I think be ought not to be cited as authority for this subgenus. 



