A 11 C A. 



VII. 



Species 42. (Mus. Cuming.) 



Aeca mtkistica. Area testd subquadrato-ovatd, gibbo- 

 siusculd, iruBquivalvi, lateribus angulato-rotundatis ; 



albd, epidermide tenui ruhidu-fuscesccnte imiiitii ; rn- 



diaiim costatd, costis tribus vel quatuor et viginti, 



vulva siuistru/is (miitihim nodulosis, dextralis anticis 

 tantum ,■ ligamenti area subangastd. 



The nutmeg Ark. Shell somewhat squarely ovate, 

 rather gibbous, iuequivalve, sides angularly rounded; 

 white, covered with a thin reddish brown epidermis ; 

 radiately ribbed, ribs three or four and twenty in 

 number, of the left valve all nodulous, of the right 

 valve the anterior only nodulous ; area of the liga- 

 ment rather narrow. 



Reeve, Pro. Zool. Soc, 1S44. 



Hub. Jimamailan, island of Negros, Philippines (found 

 in sandy mud at the depth of three fathoms) ; 

 Cuming. 



In this species there is no trace of that peculiar green 

 colour which is so prominent in the following. 



Species 43. (Mus. Cuming.) 



Akcj ch u i \xtiii m. Area testd oblongo-quadratd, sub- 

 compressd, ineequivalvi, lateribus supernl angulalis, 

 latere antico brevissimo, posticu latiore, compressd ; 

 albidd, curio corneo viridi, epidermide fused, indutd; 

 radiatim costatd, costis octo et viginti, angustis, vulvce 

 sinistralis leviter nodulosis ; ligamenti cired suban- 

 gustd. 



The copperas Ark. Shell oblong-square, somewhat 

 compressed, inequivalve, sides angulated at the 

 upper part, anterior side very short, posterior wider, 

 compressed ; whitish, covered with a green horny 

 cuticle, over which is a partial, brown epidermis ; 

 radiately ribbed, ribs eight and twenty in number, 

 narrow, those of the left valve slightly nodulous ; 

 area of the ligament rather narrow. 



Reeve, Pro. Zool. Soc, 1S44. 



Hab. San Nicolas, island of Zebu, Philippines (found in 



sandy mud at the depth of six fathoms) ; Cuming. 



The peculiar colour of this shell gives it the appearance 



of having been stained with green copperas. 



Species 44. (Mus. Cuming.) 



Am \ Luzonica. Area testd elongato-quadratd, yibbo- 

 siusculd, iti/uivu/vi. lateribus siipcrni anqulatis, infra 

 rotundatis, latere milieu brevi ; albidd, curio corneo 

 viridescente, epidermide fused, indutd; radiatim cos- 

 tatd, costis octo et viginti, latiuseulis, ruler sinistra- 

 lis subobsolet, uodu/osis ; ligamenti ureii siiliaui/iistii, 

 dec/iei. 



The Luzon Ark. Shell elongately square, rather gib- 

 bous, equivalve ; sides angulated at the upper part, 

 beneath, anterior side shorl ; whitish, co- 

 vered with a greenish cuticle, and a brown epider- 

 mis ; radiately ribbed, ribs eight and twenty in 

 number, rather broad, those of the left valve some- 

 what obsoletely nodulous; area of the ligament 

 ratlur narrow, bent inwards. 



Reeve, Pro. Zool. Sue., 1844. 



Huh Island nt Luzon, Philippines (found in sandy mud 

 at low water) ; Cuming. 

 This is a stouter shell than the preceding species; 



it is more gibbous, and the ribs are broader. 



Species 4.J. (Mus. Brit.) 



Akc.v senilis. Area testd oblique cordatd, cequivalvi, 

 superni attenuatd, lateribus rotundatis, postico sub- 

 extenso i albd, corio corneo, mutico, crasso, virides- 

 cente-fusco, indutd; radiatim costatd, costis tredecim 



nut ipialuurdeeim, lu villus, se.r scptcinvc mediums 



villi, majoribus, latioribus, ceteris plus minusve 

 obsoletis ; umbonibus prominentibus, subtilissime in- 

 curvis ; ligamenti and brevi, latiusculd. 



The aged Ark. Shell obliquely heart-shaped, equi- 

 valve, attenuated at the upper part, sides rounded, 

 posterior a little extended ; white, covered with a 

 thick, beardless, dark greenish brown, horny epi- 

 dermis ; radiately ribbed, ribs thirteen or fourteen 

 in number, smooth, the six or seven middle ribs 

 very much larger and broader than the rest, which 

 are more or less obsolete ; umbones prominent, 

 very finely curved or hooked inwards ; area of the 

 ligament short and rather broad. 



Linn^us, Syst. Nat. (Gmelin's edit.), p. 3309. 



Lamarck, Anim. sans vert. (Deshayes' edit.), vol. vi. 

 p. 473. 



February 1844. 



