820 ON MARINE SHELLS FROM THE ANDAMAN ISLANDS. [Nov. 5, 



upper valve slightly carinate from the umbo to the posterior margin, 

 the keel terminating a little above the middle, rather smooth, finely 

 concentrically striated by the lines of growth and sulcated at the umbo ; 

 covered with a thin greyish epidermis, a trifle laminated towards the 

 margin ; and from the umbo about four rather indistiuct ridges radiate 

 down the posterior half of the valve, becoming obsolete about the 

 middle of it, and again conspicuous in some specimens at the margin : 

 lower valve vastly larger than the other, very deeply and widely con- 

 centrically sulcated ; sulci fine and close together at the umbo ; 

 ridges between the sulci very thick and prominent, thicker anteriorly 

 than at the opposite extremity, and terminated in front by a sulcus or 

 depression extending from the umbo downwards at a little distance 

 from the margin, which is raised, taking the form of a stout marginal 

 ridge which terminates the beaked end of the valve ; transverse 

 grooves finely striated in the same direction : one tooth in each valve, 

 that of the upper bifurcate ; pallial sinus small ; anterior scar sub- 

 rotund, posterior more elongate. Diam. 14 mill., length 10, thick- 

 ness 8g ; the lower valve of another larger specimen is 23J mill, in 

 diameter and 16 long. 



For many years several lower valves of this species have been in 

 the British Museum with the locality "Jack's Island, South Sea," 

 attached to them. Others were presented by J. B. Jukes, Esq., in 

 1845, who dredged them at Port Essiugton in 7 fathoms, from a 

 muddy bottom ; and two specimens in the Cumingian Collection are 

 from the same place. The form, the coarse costae (which, however, 

 are sometimes rather close together), and the anterior raised and 

 beaked margin of the lower valve well distinguish the species. 



71. Crassatella radiata, Sowerby; Reeve, Conch. Icon. i. fig. 12. 

 Hab. Singapore. 



72. Arca(Scapharca)myristica, Reeve, Conch. Icon. ii. sp. 42. 

 Hab. Philippine Islands (Cuming). 



73. Pecten albolineatus, Sowerby, Thesaurus Conch, pi. 14. 

 figs. 69, 70. 



Hab. Philippine Islands. 



74. Isognomon samoensis, Baird. 



Perna {Isognomon) samoensis, Baird, ' Cruise of the Curagoa,' 

 p. 454, pi. 42. fig. 8. 



Hab. Tutuila, Samoa Islands. 



Brachiopoda. 



75. Lingula hians, Swainson ; Sowerby, Thesaurus, i. pi. 67. 

 fig. 4. 



Hab. China. 



Capt. Wilmer's notes on this species are as follows : — 

 " It lives in mud or sandy clay at low-water mark, the shell being 

 buried about a foot from the surface. It is very easily alarmed, and 



