582 MR. E. A. SMITH ON THE GENUS MYODORA. [NoV. 16, 



7. Myodora oblonga, Reeve. (Plate LIII. figs. 1, la.) 

 IMyodora oblonga. Reeve, Cou. Icon. f. 8; id. P. Z. S. 1844, 



p. 93. 



M. curvata, Reeve, I. c. f. 9 ; id. P. Z. S. 1844, p. 93. 



Hab. Mindoro Island, Philippines, and Corrigidor Islands, 



On comparison of the types of these two so-called species I fail 

 to observe any real distinctive characters ; indeed I might say they 

 are almost identical. I may add, too, that the figure of M. curvata 

 is incorrect ; the anterior dorsal slope should be less curved, and the 

 hinder end not produced to such a point. 



This species is more elongate transversely than M. ovata ; its 

 sculpture is scarcely so coarse, and is not interrupted or obsolete on 

 the posterior depressed areas of the valves ; indeed, upon the margins 

 the terminations of the plicae are quite prominent. 



8. Myodora ovata, Reeve, (Plate LIII. figs. 2, 2a.) 



Myodora ovata. Reeve, Con. Icon. f. 4 ; P. Z. S. 1844, p. 92 ; 

 Chenu, Man. de Conch, vol. ii. p. 52, f. 216. 



Hab. Zebu, Philippine Islands {Cuming) ; Port Jackson and 

 Port Adelaide {Angas) ; New Zealand {Hutton). 



In the description of this species the right valve is said to be 

 "slightly convex." This is incorrect, and should be "slightly con- 

 cave ;" for all the specimens, including the type itself, agree in this 

 respect. 



The hinder end of the convex or lower valve has a faint ridge 

 running from the umbo to the lower angle of the truncated end; and 

 upon the portion of the surface parted off by it the coarse concentric 

 plicae are all but obsolete. The corresponding end of the other 

 valve too exhibits a similar space upon which the concentric sculpture 

 is more feebly expressed ; this portion of the valve is rather excavated. 

 The microscopic sculpture of the deep valve is a trifle finer than 

 that of the flattened one, the radiating minute thread-like lines 

 upon the latter being a little more remote from one another. 



9. Myodora trigona, Reeve. (Plate LIII. figs. 3, 3a.) 



Myodora trigona, Reeve, Con. Icon, f . 2 ; P. Z. S. 1844, p. 92. 



M. tincta, Reeve, /. c. f. 5 ; P. Z. S. 1844, p. 93. 



Hab. Islands of Luzon and Ticao, Philippines. 



On comparing the types of the two species described by Reeve 

 under the above names, I have come to the conclusion that they are 

 not specifically distinct. M. tincta, judging from the description, 

 merely offers a difference of colour. It is said to be " stained with 

 light brown," a feature common to all the other species represented 

 on the same plate. The form is almost exactly the same as the 

 young of M. oblonga ; but the sculpture is finer. 



10. Myodora plana. Reeve. (Plate LIII. figs. 4, 4a.) 

 Myodora plana. Reeve, Con. Icon. f. 3 a-b ; P. Z. S. 1844, p. 92. 

 Hab. Island of Bohol, Philippines. 



