Myodora.] PELECYPODA. 1031 



side ; dorsal margin excavated, scarcely incurved ; umbones acute, 

 of a bluish tint ; right valve very ventricose, with 2 ribs from the 

 umbones to the posterior margin ; left valve flat ; trigonal liganientary 

 pit rather small. (Sowerby.) 



Diameter Ant.-post., 254 mm. ; dorso-ventral, 23-2 mm. (type). 



Type in the British Museum. 



Flab. New Zealand. 



Remarks. This species differs from M. striata in having the 

 convex or deep valve much deeper, the hinder dorsal margin pro- 

 portionally shorter, less incurved, and more sloping, the ligamental 

 pit much smaller, and the contour of the shell more rounded. (E. A. 

 Smith.) 



I have not seen this species. 



8. Myodora striata, Quoy and Gaimard, 1835. Plate 62, fig. 17. 



Pandora striata, Q. & G., Voy. Astral, iii, 1835, 537, pi 83, f. 10 ; Jay, 

 Cat. Shells, ed. 3, 120, pi. 6, f. 6, 7 ; Hartley, Cat. Rec. Biv. Shells, 50. 

 Myadora striata, Q. & G. : Reeve, P.Z.S., 1844, 93 ; Conch. Icon., ii, 

 pi. 1, f. 6; Dieff. N.Z., 255. Myodora striata, Desh. : Chenu, Man. 

 Conch., ii, 52, f. 215 ; Hanley, op. tit., pi. 12, f. 12 ; C.M.M., 62 ; Grit. 

 List, 41 ; M.N.Z.M., 137 ; E. A. Smith, P.Z.S., 1880, 579 ; Hutton, 

 P.L.S. N.S.W., ix, 514 ; Index, 88. M. brevis, Sowerby : Woodward, 

 Fischer, Man. Conch., pi. 23, f. 12 ; not of Sowerby. 



Shell rather large, ovate-triangular, inequilateral, solid, white, 

 right valve moderately convex, left valve flat, concentrically striated. 

 Beaks conspicuous, acute, directed backward. Anterior end slightly 

 shorter, angularly rounded, the dorsal margin a little convex, oblique ; 

 posterior end narrowly truncated, the dorsal margin a little excavated 

 and oblique ; ventral margin convex, straightened posteriorly. The 

 posterior dorsal area conspicuous, laterally oblique, smooth, the 

 margins sharply angled. Sculpture consisting of concentric plait-like 

 striae, strongly raised over the 2 posterior radial folds of the right 

 valve, much finer on the left valve ; microscopic sculpture consisting 

 of fine radial lines and much closer interrupted concentric lines, giving 

 the surface a minutely granular appearance, but sometimes the radial 

 lines are more prominent. Epidermis blackish-brown, persistent on 

 the posterior and ventral margins. Colour white. Interior white, 

 pearly, with a subvertical sulcus descending from the umbo to the 

 basal margin a little in front of the pallial sinus. Hinge with a rather 

 large triangular resiliurn, and a strong falciform Hthodesma. Ad- 

 ductor-scars subequal, rather high up. Pallial line distant from the 

 margin, the sinus small, convex. 



Diameter Ant.-post., 35 mm. ; dorso-ventral, 30 mm. : thickness, 

 9-5 mm. 



Type in the Mus. Hist. Nat., Paris. 



Hob. New Zealand (" Astrolabe," one left valve only). North 

 Island, and South Island as far south as Preservation Inlet, but more 



