2 DR. P. P. CARPKNTER ON NEW MOLLl SCA. 



oStain an aaiilt hliell, wliich parsed into the Cuiiiinjiian CdUcction 

 ll.iviiig reiiiovid the Hiiiinal matter witli great care, tlie \uo[) was 

 found to retain the tbnn seen in the young shell, oidy perhajis stil 

 more open. This is the first recent species of the genus which has 

 been discovered with a sculptured surface, aud afl'ords au iustruclive 

 leasuu uut to rely ou external characters. 



Terehrafnla unguicula: 1, 2, outside views of Mr. Cuming's adult specimen, 

 natural size: 3, 4, inside views of the ujper valve, slightly niagnitieii. 



The outline of the adult is much rounder, and the margin blunter, 

 than in T. caput-serpentis. Inside, the noncom])let on of the some- 

 what w-shaped loop is a very obvious character. This is large ir 

 proportion, extending to about two«-tifths of the length and one- 

 third of the greatest breadth of the shell. It is bent upwards in the 

 middle, as seen from the partly opened valves ; with a double wave at 

 the sides, as seen from the direction of the opposite valve. Two spurs 

 ascend from the crests of the side waves, as though preparing tc 

 comi)lete the loop. The similar Terehratella anyiistata from Japan, 

 when of the same size as Dr. Cooper's specimens, has the loop quite 

 continuous *. 



Subgenus NETTASTOMELLAf. 



Pholadidea : valvis postire in calycem testaceum planatum pro* 

 long at is ; calyce coviaceo nulla. 



Nettastomell/* darwinii, Sby. (diag. auct.). 



N. t. minore, elonffdta, tenitissima ; parte postiva cosfis radian* 



fihus acntiorihus circ. vii. et luminis concentricis acutissiinis. 



distantibus, ant ice continuis, eief/atitissime ornata; rostris plw 



• Dr. Cooper having forwarded for my inspection a large aud beautifully per 

 feet specimen of the true WaliUieimia californica, I have compared it with the 

 %eries of the very variable W. glohoui in the Smithsonian Museum, undoubtedly 

 from Orauge Harbour. The Calitoruia shell, however, hus a strong browuish- 

 red tiuge, aud does not display the beautiful veiuing of the Maghellan species. 



t Th. viiTTa, a duck, oriijua, mouth. The name Nefasfoma, given in tht 

 ' Brit. Assoc. Report,' ISOS, being preoccupied in another subkingdum, accuiding 

 to Dr. Cooper, it is thought necessary to .ary the termiiiatiou. 



250 



