1880.] MR. E. A. SMITH ON THE GENUS MYODOKA. 581 



they agree with the normal Australian form, except that the umbonal 

 angle is rather less acute. 



4. Myodora pandoriformis (Stutchbury). 



Anatina pandoriformis, Stutchbury, Zool. Journ. v. p. 99, tab. 

 Suppl. 43. f. 3-4. 



Myodora pandoriformis, Hanley, Rec. Biv. pi. 10. f. 9. 



M. pandorfBformis, Reeve, Con. Icon. f. 10; id. P. Z. S. 1844, 

 p. 93. 



M. hrevis, H. & A. Adams (non Sowerby), Gen. Moll. toI. iii. 

 pi. 98. f. 2, 2a. 



Hah. Port Jackson (^Stutchbury ^ Macffillivray) ; Middle Har- 

 bour (Angas^ ; Sydney Heads, 15 fathoms (Brench/ey); Port Philip 

 (Brit. Mus.) ; Stewart Island (C. Traill). 



This species is easily recognized from the others by its transversely 

 elongate form, its comparative smoothness, and the excessive fineness 

 of the microscopic sculpture. 



5. Myodora CRASSA (Stutchbury). 



Anatina crassa, Stutchbury, Zool. Journ, v. p. 100, tab. Suppl. 

 43. f. 5-6. 



Myodora crassa, Hanley, Rec. Biv. pi. 10. f. 6 ; Reeve, Con. Icon, 

 f. 1 ; id. P. Z. S. 1844, p. 92. 



Hab. Port Jackson (Stutchbury, Macffillivray, King) ; Middle 

 Harbour {Anyas, P. Z. S. 1867); Stewart Island (C. Traill). 



This species is remarkable for its solidity and its flat valve 

 being less flattened or concave than in other species of the genus. 



6. Myodora ovalis (Stutchbury). 



Anatina ovalis, Stutchbury, Zool. Journ. v. p. 100, tab. Suppl. 43. 

 f. 7-8. 



Myodora ovalis, Hanley, Rec. Biv. pi. 9. f. 53. 



Hab. Port Jackson. 



This species, judging from the figure, appears to belong to this 

 genus. It is omitted by Reeve in bis Monogragh, by Conrad in his 

 Catalogue in the fourth volume of the 'American Journal of Con- 

 chology,' and by Angas m his list of the shells of New South Wales. 

 Stutchbury's description runs thus : — " Shell inaequivalve, thin, pel- 

 lucid, posterior side truncated ; right valve convex, superior margin 

 sulcated, receiving the inflated edge of the other valve ; left valve 

 slightly convex. Hinge with an oblique elongate internal cartilage. 

 Sinus of the impression of the mantle large." 



The figure is rather like that of Myodora pandoi-iformis as regards 

 form ; but the sculpture of the deep valve appears finer. The 

 pallial sinus is said to be large, which is hardly descriptive of that 

 in pandoriformis, or, indeed, of any species of the genus. Indeed, 

 this fact and its " thin, pellucid " substance suggest the possibility 

 of its belonging to another group — Thracia'l 



