270 GINGLYMACONCHA. MYAD. 
Mya striata, Linn. Syst. Nat. xii. 1111. no. 21; Gualt. Test. | 
t. cv. f. F.; Chem. Conch. viii. t. cii. f. 864-866; Gmel. 
Syst. Nat. 3215; Donov. Brit. Shells, t. exvii.; Mont. 
Test. Brit. 26; M. § R. Trans. Linn. Soc. viii. 32 ; Flem. 
Edinb. Encyel. vi. ; Turt. Conch. Dict. 105. 
Pholas conoides, Parsons, Act. Angl. 55. t. i. f. 1-4. 
Pholas Nanus, Pult. Cat. Dorset. 27. t. i. f. 7. 
This elegant shell was first discovered off Tenby by Mr. 
Lyons, and has since been found in the Plymouth Sound by 
C. Prideaux, Esq. ; off the western coasts of Cornwall by Mr. 
J. Cranch, and in Bantry Bay, Ireland, by the late Miss 
Hutchings. 
STIRPS II. 
The shells shut anteriorly ; the umbones nearly central. 
Montagu referred the genera of this Stirps to one of his ar- 
iificial genera called Ligula (a name long before adopted te 
distinguish a genus of intestinal worms, which is still in use), 
and associated them with those of the following family, the 
Abrade. 
Genus 18. THrRacta. 
Shells with the right valve most convex ; umbones placed a 
little behind the middle of the shell: epidermis thin; the 
process that bears opening ligament gradually formed: ligament 
slightly projecting, as if simply hinge-shaped. 
* The process bearing the ligament small elongate. 
1. THRACIA CONVEXA. 
Shells ventricose, smooth, slightly ploughed, the interstices 
striolated, truncated behind, the angles rounded. Length two 
inches and a half; height nearly two inches. 
Ligula distorta (adulta), Mont. Test. Brit. Supp. 166. 
Mya convexa, Wood, Gen. Conch. i. 92. t. xvii. f. 1; Turt. 
Conch. Dict. 101. 
This very rare species has been taken occasionally in Saleombe 
Bay and in the Plymouth Sound. 
