MACTRA. 



Plate II. 



Species 5. (Mus. Cuming.) 



Mactra sulcataria. Mact. testa ovato-trmisversa, suh- 

 aquilateraU, turgiduld, ittrdqne extremitate aqualiter 

 obtmd, transversim sulcata, ad mnboues l(evigatd,Jlavd, 

 umhonibus dejn-essis, violaceis, alio radiatis ; lunula 

 aredque magnis, eleganter pUcatis ; valvis intus albo- 

 fiavescentibus ,• card'me angusto, fossuld UgamenU ob- 

 Uqnd ; deiitibiis lateralibus compressls, brevibns. 



The grooved Mactra. Shell ovately transverse, nearly 

 equilateral, rather swollen, equally obtuse at each ex- 

 tremity, transversely grooved, smooth at the umboes, 

 yellowish, umboes depressed, violet, white-rayed ; 

 lunule and area large, elegantly plaited ; valves 

 whitish-yellow within ; hinge narrow, Ugamentary 

 pit oblique ; lateral teeth compressed, short. 



Deshayes, Pro. Zool. Soc. 185-t. 



Hah. ? 



Chiefly distinguished by its transverse concentric 

 grooves, which converge neatly on each side in the area 

 and lunule. 



Species 6. (Mus. Cuming.) 



Mactra cordiformis. Mact. testd suhtrigond, tenni, 

 ventrkosd, vLv cequilaterali, extremitate posticd siib- 

 productd, transversim minute striata, umbones versus 

 ItEvibus ; liinuld aredque subamplis, subtiliter plicato- 

 liratis ; Jlacescente-albd, umbones versus ferrugineo- 

 fusco sparsim tinctd et marmoratd, intus alba. 



The heart-shaped Mactra. Shell subtriangular, thin, 

 veiitricose, scarcely equilateral, posterior extremity 

 rather beaked, transversely minutely striated, smooth 

 towards the umboes ; lunide and area rather large, 

 delicately plicately ridged ; yellowish-white, sparingly 

 mottled and stained with rust-red towards the um- 

 boes, white interiorly. 



Deshayes, Pro. Zool. Soc. 1854. 



Hah. ? 



A thin veutricose subtriangular species, finely striated, 

 almost smooth, the strise gathering into the area and lu- 

 nule in fine close-set plait-like ridges. The shell is of a 

 yellowish-white, zigzag-mottled, and stained about the 

 umboes with lis'ht rust-red. 



Species 7. (Mus. Cuming.) 



Mactra inflata. Mact. testd subtrigono-ovatd, parum 

 tumidd, vix aquilaterali, latere antico breviusculo, 

 poslico suiangulato-truncato ; lunuld indistinctd, ared 

 magna ; albidd, violascente tinctd et radiatd, umboni- 

 /jus violaceis, intus albd. 



The inflated Mactra. Shell somewhat triangularly 

 ovate, but little swollen, scarcely equilateral, anterior 

 side rather short, posterior rather angularly trun- 

 cated ; lunule indistinct, area large ; whitish, stained 

 and rayed with pale violet, umboes violet, interior 

 white. 



Brown, Philippi, Enum. Moll. Sicilise, p. 11. pi. 3. f. 1. 



Hab. Naples. 



It is somewhat doubtful whether this is not a variety of 

 the M. stultonmi, though more solid and compressed than 

 the typical form of that species. 



Species 8. (Mus. Cuming.) 



Mactra solidissima. Mact. testd transverse oblongd, 

 crassiusculu, sordidi albd, epidermide Jlavescente-fuscd 

 indutd, inrpquilaterali, latere postico longiore, paulu- 

 lum Jiiante ; lumdd aredque subindistinctis ; fovea car- 

 dinali perampld, trianrjuluri, impressione pallii pos- 

 tice indentatd. 



The very solid Mactka. Shell transversely oblong, 

 rather thick, dirty-white, covered with a yellowish- 

 brown epidermis, inequilateral, posterior side the 

 longer, a little gaping ; lunule and area rather in- 

 distinct ; hinge-pit very large, triangular, impression 

 of the mantle indented posteriorly. 



Chemnitz, Conch. Cab. vol. x. pi. 170. f. 1656. 

 Mactra giguntea, Lamarck. 



Huh. United States (about sandy beaches) ; Gould. 



Dr. Gould, of Boston, United States, describes this 

 large species as living abundant about the sandy beaches 

 of Massachusetts. At low water it is dug out of the sand 

 with shovels ; at higher tides, when the shell is open, the 

 fishermen wade into the water, thrusting a pointed stick 

 into the sand before them as they walk along. Whene th 

 stick passes between the valves, the animal closes the sheU 

 upon it and is drawn up. 



March, 1854. 



