Zoological Society. 63 



Ifuh. Baclayon, island of JJohol, Philippines (found in pandy mud 

 at the dojjth of seventeen fathoms) ; Cuming. 



This species is chiefly distinguished from its congeners, the Mya- 

 (lorec tinctu and triyona, by its more oblong shape. 



4. Myauora ovata. Myad. testd ovatd, suhtriangulari, valvd 

 sinistrd ventricoso-concavd, dextrd leviter convexd, concentric^ 

 striata, striis elevatis, prope maryincm anticavi suhobsoletis, valvcB 

 dextrtc niimeroiiis, confertis, sinistra; pronmientibus, subdistantibus, 

 umbonibus depresso-incurvis. 



Conch. Iconica, Myadorti, pi. 1. f. 4. 



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

 mud at the depth of six fathoms) ; Cuming. 



This species exhibits a greater disparity in the sculpture of the 

 valves than any other, the striae of the right valve being very fine and 

 close-set, whilst those of the left are almost keel-like and compara- 

 tively distant. 



5. Myadora tincta. Myad. testd triyona, antici subtruncatd, 

 usque maryinem concentrice striatd, striis elevatis, prominentibus ; 

 fusccscenle tincta. 



Conch. Iconica, Myadora, pi. 1. f. 5. 



Hab. Island of Ticao, Philippines (found in coral sand at the depth 

 of six fathoms) ; Cuming. 



The Myadora tincta scarcely differs from the Myadora plana, ex- 

 cept in being of a less oblong and more triangular form. 



6. Myadora striata, Gray, MSS. British Museum ; Pandora 

 striata, Deshayes. 



Conch. Iconica, Myadora, pi. 1. f. 6. a, b, and c. 

 Hab. Port Nicholson, New Zealand ; Swainson. 

 This is the grand type of the genus, and of much larger size than 

 any other species. 



7. Myadora erevis. Anatina brevis, Stutchbury, Zcol. Journ. 

 vol. V. p. 99 ; Tab. Supp. xliii. f. 1 and 2. 



Conch. Iconica, Myadora, pi. 1. f. 7. 



This is a very interesting form, and the striae of the left valve are 

 peculiarly wrinkled. 



8. Myadora oblonga. Myad. testd trigono-oblongd, antice latis- 

 sinie truncatd, concentrice striatd, striis elevatis, regularibus , prope 

 marginein anticam angulatis. 



Conch. Iconica, Myadora, pi. 1. f. 8. 

 Hab. Island of Mindoro, Philippines ; Cuming, 

 llie anterior side of this species is the most broadly truncated of 

 any. 



9. Myadora curvata. Myad. testd curvato-oblongd, valvd dextrd 

 convexiusculd, antice subindistincte flexuoso-costatd, concentrice 

 striatd, striis elevatis, angustis, regularibus. 



Conch. Iconica, Myadora, pi. 1. f. 9. 



Hab. Island of Corrigidor, Philippines ; Cuming. 



This species differs also in form rather than in variety of sculpture. 



