MYADORA— Plate I. 



Species 1. (Mus. Cuming.) 



Myadora cbassa. Myad. testd trigono-orbiculari, sub- 

 solidd, vulva dextrd concaviusculd ; valvis concentrice 

 striatis, striis elevatis, subdistantibus, versus mar- 

 ginem obsoletis, carind indistinctd prope marginem 

 anticam ab umbonibus divergente ; umbonibus elevatis. 



The thick Myadora. Shell triangularly orbicular, 

 risrht valve rather concave; valves concentrically 

 striated, striae raised, rather distant, obsolete to- 

 wards the margin, with an indistinct keel diverging 

 from the umbones near to the anterior edge. 

 Anatina crassa, Stutchbury, Zool. Journ., vol. v. 

 p. 100, Tab. Supp. 43. f. 5 and 6. 



Hab. ? 



This short rounded species is the only one I have 



seen at present in which the right valve is concave. 



Species '2. (Mus. Cuming.) 

 Myadora trigona. Myad. testa trigond, valde plano- 

 depressd, usque marginem concentrice striata, striis 

 prominent ibus, rjuasi carinu/atis, prope marginem an- 

 ticam undatis ; umbonibus acutissim'e mucronato- 

 elevatis. 

 The triangular Myadora. Shell triangular, very 

 flatly depressed, concentrically striated to the edge, 

 striae prominent, keel-like, waved on approaching 

 the anterior margin ; very sharply pointedly raised. 

 Reeve, Pro. Zool. Soc, 1S44. 

 Hab. Island of Luzon, Philippines ; Cuming. 



Four odd valves only of this interesting little species, 

 in which the concentric striae are remarkably prominent 

 and keel-like, were found by Mr. Cuming at the above- 

 mentioned island. 



Species 3. (Fig. a and b, Mus. Cuming.) 



Myadora plana. Myad. testd trigono-ob/ongd, autic'i 

 subtruncatd, planissimd, concentrick striata, striis 

 elevatis, subdistantibus, valva sinistra- prominentibus . 



The flat Myadora. Shell triangularly oblong, slightly 

 truncated anteriorly, very flat, concentrically stri- 

 ated, stria raised, rather distant, those of the left 

 valve the more prominent. 



Reeve, Pro. Zool. Soc, L844. 



Hab. Baclayon, island of Bohol, Philippines (found in 

 sandy mud at the depth of seventeen fathoms); 

 Cuming. 



This specie.- is chiefly distinguished from its conge- 



ners, the Myadora: tincta and trigona, by its more oblong 

 shape. 



Species 4. (Mus. Cuming.) 

 Myadora ovata. Myad. testd ovatd, sitbtriangutari, 

 valvd sinistra ventricoso-concavd, dextrd leviter con- 

 vexd, concentrice striata, striis elevatis, prope mar- 

 ginem anticam subobsoletis, vaivee dextra numerosis, 

 confertis, sinistra prominent ibus, subdistantibus •, 

 umbonibus depresso-incurvis. 

 The ovate Myadora. Shell ovate, somewhat trian- 

 gular, left valve ventricosely concave, right valve 

 slightly convex, concentrically striated, striae raised, 

 somewhat obsolete near the anterior margin, those 

 of the right valve numerous and close, of the left 

 valve prominent and rather distant ; umbones de- 

 pressly incurved. 

 Reeve, Pro. Zool. Soc, 1844. 



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 sculp- 

 ture of the valves than any other, the stria? of the right 

 valve being very fine and close-set, whilst those of the 

 left are almost keel-like and comparatively distant. 



Species 5. (Mus. Cuming.) 

 Myadora tincta. Myad. testd trigond, antie'e subtrun- 

 catd, usque marginem concentrice striata, striis ele- 

 vatis, prominentibus ; fusceseenle tincta. 

 The stained Myadora. Shell triangular, slightly 

 truncated anteriorly, concentrically striated to the 

 margin, striae raised, prominent ; stained with light 

 brown. 

 Reeve, Pro. Zool. Soc, 1844. 



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

 at the depth of six fathoms) ; Cuming. 

 The Myadora tincta scarce!}' differs from the Myadora 

 plana, except in being of a less oblong and more tri- 

 angular form. 



Species 6. (Mus. Norris.) 

 Myadora striata, Myad. testa triguno-ovuta, plana, 

 an tie, leviter fleXUOSd, concentrice striata, striis 1111- 



merosis, confertis, irregularibus ; depressions untied 

 concavii ; cardine uppendice testaced munito. 

 The striated Myadora. Shell triangularly ovate, flat, 

 slightly rltxuous anteriorly, concentrically striated, 



