GINGLYMACONCHA. ARCADE. 3a/ 
umbones incurvated, very remote from one another; the mar- 
gin gaping, and not in the least denticulated.” Length seven- 
eighths of an inch; height six-eighths of an inch. 
Arca Nox, Rumph. Mus. t. xliv. f. P. ; Linn. Syst. Nat. 1140. 
no. 169; Borlase, Cornw. t. xxvii. f. 15-16; Donov. Brit. 
Shells, x. t. clvi. f. 2; Mont. Test. Brit. 139. t. iv. f. 3; 
M. § R. Trans. Linn. Soc. viii. 91; Schroét. Einl. ui. 260 ; 
Lam. Hist. Nat. des Anim. sans Vert. part. 1.37; Dill. Desc. 
Cat. 226; Turt. Conch. Dict. 99. 
Arca fusca, Mont. Test. Brit. Supp. 51; Turt. Conch. Dict. 
10; Flem. Edinb. Encycl. 97. 
Arca tortuosa, Penn. Brit. Zool. iv. 97. t. lviii. f. 57. 
Area Noe, Lister, Conch. eccexxxvil. f. 208; Poli, Test. ii. t. 
xiv. f. 1,2; Brug..Encycl. Méth. t. eccv. f. 2, a, 6. 
Testa junior. 
Arca minima, Turt. Conch. Dict. 8. 
Var. 3. The strize on the area very close together, and an- 
gulately reflexed. 
Var. 6. The cardinal area spotted with white, and with less 
strie. 
2. ArcA PENNANTIANA. 
Shells diaphanous, rhomboidal, sculptured with obsolete, de- 
cussating striz; the umbones recurved; the margins crenu- 
lated. Length one inch; height three-eighths of an inch. 
Arca barbata, Penn. Brit. Zool. iv. 98. t. lvim. f. 59; Dill. 
Dese. Cat. 229. 
Arca lactea, Da Costa, Brit. Conch. 171. t. ii. f. 5; Donor. 
Brit. Shells, t. exxxv.; Born. Mus. 89 ; Schroét. Einl. i. 
266; Brug. Encycl. Méth. Vers. 101. t. eccix. f. 1; Bonan. 
Reer. t. i. f. 79; Kirch. t. uu. f. 79; Gualt. Test. t. xi. f. 
F; Knorr. Mus. ii. t. ii. f. 7; Mont. Test. Brit. 138; M. 
§ R. Trans. Linn. Soc. viii. 92; Flem. Edinb. Encycel. vii. 
92; Dill. Desc. Cat. 236. 
Arca crinita, Pult. Cat. Dorset. 54. t. ul. f. 5. 
Area perforans, Turt. Conch. Dict. 9. 
