70 



MOLLUSCA. 



[OsTRACEA. 



Mat on and Rackett, p. 102; Lamarck, VI, pt. 1st, p. 228; 

 Fleming, p. 395 ; Brown, Ency. Brit., p. 422 ; lb., Wernerian 

 Mom., p. 514 ; Turton, Biv., p. 229, pi. 18, f. 5, 6, 7 ; Forbes, 

 p. 38. 



Shell suborbicular, smooth, thin, membranaceous, and trans- 

 parent, generally much compressed; convex valve a little 

 thickened; Hat valve very thin, with a large perforation, for the 

 size of the shell ; outside dull yellowish-white, with very indis- 

 tinct, concentric wrinkles, or lines of growth, which can only 

 be seen by the aid of a strong lens ; inside white, with pale 

 iridescent reflections ; plug tendinous, very seldom hard at the 

 base, with the termination testaceous ; umbones small, flat, and 

 pointed. 



Common on all the British and Irish coasts, adhering to 

 shells, stones, and Fuci. 



4. Anomia aculeata, pi. XXII, f. 6. 



Anomia aculeata, First Ed., pi. 34, f. 6 ; Gmelin, Syst., p. 

 3346; Midler, Zool. Dan. Prod., p. 3005; Montagu, p. 157, 

 pi. 4, f. 5; Fleming, Edin. Ency., p. 98; lb., Brit. An., p. 396; 

 Brown, Ency. Brit., p. 422; lb., Wernerian Mem., p. 514; 

 Maton and Rackett, p. 103; Turton, Biv., p. 233. 



Shell thin, compressed, orbicular, or slightly oblong; with 

 numerous raised, divergent, interrupted striae, which are sur- 

 mounted with many small concave, obtuse murications, or 

 spines; umbones small, turning a little downwards; upper valve 

 convex; under valve quite flat and smooth, but sometimes pro- 

 vided with small murications towards the margin ; perforation 

 of medium size, and situate near the hinge ; generally of a pale 

 dull brown, or cream-white; inside white, and slightly pcarlace- 

 ous. Diameter three-eighths of an inch. 



Found on many of our coasts, adhering to the roots of Alga, 

 stones, the legs of crabs, &c. 



5. Anomia cylindutca, pi. XXII, f. 7, 8. 



Anomia Cymhifovmis, First Ed., pi. 34, f. 7, 8 ; Maton and 

 Rackett, Linn. Tr., VIII, p. 104, pi. 3, f . 6 ; Fleming, Edin. 

 Ency., p. 98 ; Anomia cylindrica, Schroeter, p. 3, pi. 9, f • 9 ; 

 Brown, Ency. Brit., p. 422 ; Fleming, p. 395 ; Turton, Biv., p. 

 232 ; Forbes, p. 39. 



Shell oblong-oval, convex, somewhat cylindrical ; beaks re- 

 curved, narrower towards the umbones ; upper valve convex, 

 and curving over the under one, which is concave and smooth ; 

 surface of upper valve dull brown, with a few transverse, obscure 

 wrinkles. Length half an inch ; breadth a quarter. 



Inhabits many of our coasts, adhering to Fuci, Serlularia, &c. 



6. Anomia electrica, pi. XLVI, f. 5. 



Patella pellucida, First Ed., pi. 10,* f. 5; Brown, Wernerian 

 Mem., II, p. 514; Anomia electrica, Linne, Syst., p. 1151; 

 Chemnitz, VIII, p. 79, pi. 76, f. 691 ; Turton, Biv., p. 226, pi. 

 17, f. 8, 9. 



Shell orbicular, very thin, pellucid, slightly wrinkled concen- 

 trically; umbo small and margined, below which is a chalky-like 

 spot, of a roundish shape; upper valve very convex; under valve 

 very flat, with an extremely large interrupted perforation; whole 

 shell of a bright, amber-colour. Diameter about an inch. 



I first found this species at Color Cots, near Tynemouth, and 

 afterwards at Dublin Bay and Portmamock, Ireland. 



7. Anomia cepa, pi. XXXIX, f. 12. 



Anomia ccpa, Linne, Syst., p. 1151; Chemnitz, VIII, p. 85, 

 pi. 76, f. 694, 695 ; Turton, Biv., p. 229, pi. 18, f. 4, young. 



Shell generally oblong, suboval, compressed, and rough exter- 

 nally, but not undulating ; beaks terminal ; under valve thin, 

 but not scaly ; yellowish fawn-coloured externally, and rosy red 

 within. Length nearly two inches ; breadth one and a half. 



Young shells are somewhat triangular, with their sides ob- 

 tusely cut down. 



Found by Dr. Turton, near Broadsands, Torbay, at the very 

 lowest Spring tide. 



8. Anomia punctata, pi. XXXIX, f. 13. 



Anomia punctata, Gmelin, Syst., p. 3346 ; Chemnitz, VIII, 

 p. 88, pi. 77, f. 698 ; Turton, Biv., p. 231, pi. 18, f. 1 1. 



Shell orbicular; beaks terminal; upper valve convex, covered 

 with numerous raised dots ; under valve flat, with small and 

 numerous punctures ; base somewhat truncated. Diameter 

 about an inch. 



Found on crabs and shells, on the south coasts of England. 



9- Anomia fornicata, pi. XXXIX, f. 14, 15. 



Anomia fornicata, Lamarck, VI, pt. 1st, p. 228; Turton, 

 Biv., p. 234, pi. 18, f. 12, 13. 



Shell dirty white, somewhat orbicular, compressed, finely 

 striated ; upper valve convex, provided with a vaulted chamber 

 near the back ; hinge pointed, and nearly terminal ; sides near 

 the margin irregularly sinous, with numerous, very fine, radi- 

 ating stria), and with fine, regular, transverse striae near the 

 hinge ; under valve flat, with the perforation round, and nearly 

 closed ; inside of a silvery metallic lustre ; margin provided 

 with fine, longitudinal striaj, the hollow vaulted chamber, which 

 is considerably curved on one side, and scaly externally. Dia- 

 meter about half an inch. 



Found at Torbay. 



10. Anomia striolata. 



Anomia striolata, Turton, Biv., p. 233. 



Shell oval, somewhat cylindrically convex, and longitudinally 

 striate, with recurved beaks. 



Dr. Turton says this shell resembles the A. cylindrica, in all 

 respects, "but is always marked with fine, rather remote, longi- 

 tudinal raised lines." 



Found in the roots of Fuci. 



11. Anomia tubularis. 



Anomia tuhidaris, Turton, Biv., p. 234. 



Shell cream-white, orbicular, with the perforation of the 

 under valve entire all round, and forming a raised cylindrical 

 tube ; beak terminal ; plug tendinous. 



Found attached to Fuci. 



The two latter shells arc very doubtful species ; they are 

 given on the authority of Turton. 



Genus 4 Ostrea Linnaeus. 



Shell inequivalve, irregular, and foliacoous; umbones some- 

 what separated, and of unequal size ; lower valve largest, con- 

 cave, and frequently adherent ; upper valve smaller, and some- 

 what plain ; hinge destitute of teeth ; ligament partly external ; 

 the facet to which it is attached is subtrigonal, tripartite, and 

 divided by two elevated lines, which divaricate from the umbo ; 

 each valve provided with two muscular impressions, the one 

 large, suborbicular, and nearly central, the other very small, and 

 situate near the hinge. 



