PETKICOLA.— Plate II. 



Phohf nipeidhi, Claiuvillo. 

 Hub. British shores. 



The species is subject to great variations in form 

 and sculpture, which have given rise to uuiuy needless 

 synonyms. 



Species 12. (Mus. Brit.) 



Petricola ELLirTiCA. Pit. tcxti'i (Jj/onyo-elliptin'i, mh- 

 fniiipnssi'i, riKliiifiiii sulcata, conceiitrice distanier 

 lamhhili'i : lilt' rr imtico bivviilsculo, rotundato ; 

 latere postko pivilucto, ad teiminmn vix angulato ; 

 margvie dorsali rectiusndo. 



The ellpitical Petricola. Shell oblong-elliptical, 

 subcompressed, radiately grooved, concentrically 

 distantly laminated; anterior side rather short, 

 rounded; posterior side produced, scarcely angular 

 at the end ; dorsal margin rather straight. 



SowEiiBV. Proc. Zool. Soc, 1834. 



Hah. Payti, Peru. 



This rather Yenus-liko species is found in hard mud 



at low water. 



Species lo. (Mus. Brit.) 

 PEnncoLA cuLN-KNSis. Pct. testd Itrevi, snbcicneatd, 

 radiiitim stiiatd ; aiitice brevissima, rotundatd, 

 iiijlatd, sfriin tennibus radiatd ; pnstice subattenuatd, 

 aiifjidatd, ante angnlum depret<sd, subcontractd, post 

 angulum costis elevatis acutis radiatd, ad terminum 

 truncatd ; margine dorsali dedici. 



The Chinese Petricola. Shell short, subcuneate, 

 radiately striated ; anteriorly very short, rounded, 

 inflated, rayed with thin strise ; posteriorly rather 

 attenuated, angular, rayed with raised, sharp ribs, 

 truncated at the end ; dorsal margin sloped. 



Deshayes. Proc. Zool. Soc, 1853. 



Hab. Chinese Seas. 



Differing from Petricola lithophaga in having strong 

 sharji ribs behind the posterior angle. 



Species 14. (Mus. Brit.) 



Petimcola hipartita. Pet. testa breciusciUd, sub- 

 cuneiita, antic'c brevi, injlatd, divaricatim striatd ; 

 puslici' subattenuatd, angidatd, post angulum costis 

 viiliilis sirratis radiatd, ad terminum frinicutd : 

 tiiiihinuhiif pivmiiiuutib'US, aciUis ; nuinjiiic ducfiiti 

 dcctiri. 



The nn'ARTiTE Petricola. Shell rather short, suli- 

 cuneate, anteriorly short, inflated, divergently 

 striated ; posteriorly rather attenuated, angidar, 

 rayed behind the angle with strongly serrated ribs, 

 truncated at the end; umboos prominent, sharp ; 

 dors.al margin .sloped. 



Deshayes. Proc. Zool. Soc, 18.i.3. 



Ifab. Island of Samar, Philippines. 



Species U. (Mus. Brit.) 



Petricola solida. Pet. testa subglobosd, solidd, injlatd, 

 j)rope iimbones virinque violaceo-fuscd, concentric!: 

 distanter laminatd, radiatim serrato-costellatd ; 

 latere antico bred, rotundo ; latere postico sub- 

 acmninato. 



The solid Petricola. Shell rather globose, solid, in- 

 flated, violet-brown on each side of the umboes, 

 concentrically distantly laminated, with radiating 

 serrated small ribs; anterior side short, round; 

 posterior side rather acuminated. 



SowERRY. Proc. Zool. Soc, 1834. 



Ilab. Peru. 



Collected by the late Mr. Cuming in hard clay and 

 I stones at Lambezeque. 



