260 TESTACEOUS MOLLUSCA. 



thin, fragile, blue or purplish, with a dark brown almost black 

 subradiated epidermis ; hinge-margin elongated and straight; an- 

 terior margin direct and emarginated. lj. — Sandwich Isles. 1 



MALLEUS. 



Subequivalve, rugged, distorted frequently elongated; sublobate at 

 the top; beaks small, diverging ; hinge without teeth, with an 

 elongated conical furrow under the beaks ; ligament subexternal, 

 short, placed in the sloping area, at the top of the valves. 



M. Albus. Lam. 1. Ostrea Malleus Albus. Ch.f. 2029,0. 

 — O. Malleus Var. D. p. 273. — Hammer-shaped, the hinge-mar- 

 gin being elongated on either side of the subcentral beaks, and the 

 shell being produced ventrally in an elongated narrow, very tortu- 

 ous, (generally) straight lobe, white usually speckled with rust-co- 

 lour : smooth, the small portion of internal nacre bluish black : beaks 

 scarcely projecting. Young. M. Normalis Sow. G. — Reeve t. 

 107. f. 2.— Ostrea Anatina TV. t. 11. /. 59. The anterior lobe 

 not yet developed. 8. Australia. China 7 . No particular sinus 

 for the byssus. 



M. Vulgaris. Lam. 2. — Sow. G. — Reeve. Sys. t. 107. /. 1. — 

 Bl. t. 63. f. 4.— £. t. 177. f. 12.— Ostrea Malleus Lin. 1147. 

 — D.p. 272.— Ch.f. 655.— TV. t. 11./. 58. Shape of the last, but 

 black, coarse, more tortuous; the sinus for the byssus distinct from 

 the ligamental cavity. 8. Indian Ocean. The figure 656 of Chem- 

 nitz is considered by Lamarck, a white variety of this species. 



M. Normalis. Lam. 3. — Del. t. 14. /. 4, 5. -Elongated, 

 broad, tortuous, the dorsal edge forming an anterior lobe, but no 

 posterior one. Var. A. Yellowish, speckled with brown, and 

 within whitish, with the space occupied by the animal, bluish black ; 

 the lobe short. Var. B. Black, anterior lobe long. 5. Australia, 

 the var. B. Indian Ocean. Distinguished from the young of Albus by 

 the lobe being anterior, and the shell broader in proportion, from 

 Vulsellatus by being tortuous. 



M. Vulsellatus. Lam. 4. — Bl. t. 65. bis. f. 4. — Ostrea 

 Regula Forskael Desc. Anim. p. 124. — Ch. f. 651. — D. p. 273. 

 Elongated, flattened, purplish black, lamellar, flexuous but not tor- 

 tuous, narrow edges of the sides subparallel : hinge margin short, a 

 very small anterior lobe; a distinct bysseal sinus: internal nacre 

 white, the scar black. 6. Red Sea, Madagascar. 



M. Anatinus. Lam. 5. — Ostrea A. Gmel. 3333. — O Figu- 

 rata. D.p. 273.— Ch. f. 658,9.— E. t. 177. /. 14. Oblong- 



1 See too P. Quadrata of Anton in Wiegman's Archives, 1837, 

 also P. Planorbis and RupellA of Thifo in the Ann. de se. nat. 2d. 

 series vol. 14. 



