Myodora. \ PELEOYPODA. 1025) 



unequal, the anterior elongate, the posterior round. Pallial sinus 

 shallow, biangulate, straight in front. 



Diameter Ant. -post., 29 mm. ; dorso-ventral, 25 mm. thickness, 

 7 mm. 



Type in the British Museum. 



Hob. New Zealand (Colonel Bolton). Stewart Island, in 14 

 fathoms (C. Traill). Also Australia and Tasmania. 



4. Myodora crassa, Stutchbury, 1835. Plate 55, fig. 12. 



Anatina crassa, Stutchbury, Zool. Journ., v, 1835, 100, Tab. Sup., 43, f. 5, 6. 

 Myodora crassa, Stutchb. : Reeve, P.Z.S., 1844, 92 ; Conch. Icon., ii, 

 pi.' 1. f. 1 ; Hanley, Cat. Rec. Biv. Shells, 25, 339, pi. 10, f . 6 ; E. A. 

 Smith, P.Z.S., 1880, 581 ; Button, P.L.S. N.S.W., ix, 516 ; Chall. Rep. 

 xiii, 65 ; Index, 88. 



Shell small, sub triangular, thick, subequivalve, transversely ribbed, 

 left valve less flat or concave than in most other species of the genus. 

 Anterior end slightly longer, convex, the dorsal margin long, lightly 

 convex, very oblique ; posterior end subtruncated, the high dorsal 

 margin rapidly descending, faintly convex, both valves carinated, 

 with a smooth cordate posterior depression. Sculpture consisting of 

 distinct concentric lirse and fairly coarse microscopic radiate striae. 

 Colour yellowish-white. Pallial sinus not deep. 



Diameter Aiit.-post., 13 mm. ; dorso-ventral, 10*5 mm. 



Type in the British Museum. 



Hob. Stewart Island (C. Traill). Also Australia. 



I have not seen this species. 



5. Myodora novae-zealandiae, E. A. Smith, 1880. Plate 55, figs. 13, a. 



Myodora novce-zealandice, E. A. Smith, P.Z.S., 1880, 584, pi. 53, f. 5 ; Index, 

 88. M.neozelanica, Smith : Hutton, P.L.S. N.S.W., ix, 516. 



Shell small, subequilaterally triangular, concentrically coarsely 

 ribbed, right valve considerably convex, the left a trifle concave, 

 solid, light brown. Beaks conspicuous, acute, slightly curved back- 

 ward. Anterior end slightly longer, obtusely angled, the dorsal margin 

 nearly straight, very oblique ; posterior end subtruncated, the dorsal 

 slope feebly incurved ; basal margin broadly convex, ascending pos- 

 teriorly. Sculpture consisting of rather coarse distant concentric 

 riblets, finer on the left valve ; right valve with an indistinct shallow 

 groove posteriorly near the margin, where the concentric lirse sud- 

 denly stop, leaving a smooth narrow space between their termi- 

 nation and the edge i.e., a plain posterior dorsal area ; the surface of 

 both valves minutely microscopically granular. Colour light brown. 

 Interior pearly, marked with 2 subparallel or slightly diverging rays or 

 striae, radiating from the umbo a little beyond the centre of the valves. 

 Margins smooth, sharp. Hinge with a small central resilium and oval 

 lithodesma. Adductor-scars unequal, the anterior scar semicircular, 

 the posterior a little higher up and round. Pallial sinus not deep, 

 convex. 



