GINGLYMACONCHA. PINNADZ. 335 
t. cexviil. f. 2; Pult. Cat. Dorset. 38. t. xii. f. 5; Donov. 
Brit. Shells, t. exxviti.; Mont. Test. Brit. 159; M. & R. 
Trans. Linn. Soc. viii. 105; Flem. Edinb. Encycl. vii. 99 ; 
Lam. Hist. Nat. des Anim. sans Vert. vi. part. i. 126 ; Dill. 
Dese. Cat. 309; Turt. Conch. Dict. 109. 
Varietas pygmea. 
Mytilus incurvatus, Penn. Brit. Zool. 110. t. Ixiv. f. 54; 
Mont. Test. Brit. 159; M. & R. Trans. Linn. Soc. viii. 
106. t. mi. f. 7; Flem. Edinb. Encycl. 99; Turt. Conch. 
Dict. 109. 
The shells with their valves thick; under the epidermis 
blue, radiated with blue and white ; the epidermis very smooth, 
polished, purple-black or black; in young specimens radi- 
ated with blue and white. 
This species is very common in the European seas, in estu- 
aries, and between rocks on the shores of the sea, adhering to 
the rocks by their byssus. 
2. MyYTILUS PELLUCIDUS. 
Shells oblong, curved and compressedly-angulated anteriorly ; 
behind cbtusely rounded ; very much incurvated towards their 
inferior margin; the teeth undulated and arranged in a single 
series. Length three inches; height one and three-eighths 
of an inch. 
Mytilus pellucidus, Penn. Brit. Zool. iv. 112. t. xin. f. 75 ; 
Chem. Conch. vii. t. Ixxxiv. f. 755; Donov. Brit. Shells, 
t. Ixxxi.; Mont. Test. Brit. 160; M. & R. Trans. Linn. 
Soc. vil. 107; Flem. Edinb. Encyel. vii. 99; Dill. Desc. 
Cat. 310; Turt. Conch. Dict. 110. 
Mytilus edulis, 6., Lam. Hist. Nat. des Anim. sans Vert. vii. 
part. i. 126. 
This species differs from Mytilus edulis, in having their 
valves more compressed, thinner and whitish under the epi- 
dermis; in the inferior margin being rather more tumid, and 
under the umbones gibbosely produced, and in the umbones 
being more approximating to each other. 
The shells of young specimens are pale purple-black, rayed 
with blue. 
