PLACUN ANOMI A 



Plate II. 



0. (Fig. a, i, c, Mus. Cuming.) 



Pl.^cunanomia ione. Plac. testa suborbiculari, aMndd, 

 laminari, laminarum, margine spiculis parvis elonyalis 

 imlructo, perforatione maxima ; intus virente. 



The violet Placunanomia. Shell nearly orbicular, 

 whitisb, laminar, edge of the laminaj furnished with 

 small elongated processes, perforation verj' large ; 

 interior green. 



Gkay, Pro. Zool. Soc. 1S49, p. 123. 



Ha6. Sydney, Australia (on rocks) ; Strange. 



The smooth portion of the upper surface of this shell, 



described by Dr. Gray as being laminar, appears to be an 



abrasion of the radiating spicular processes occasioned by 



the attachment of some other shell. 



Fig. a represents the plug or tendon of adhesion. Fig 6 



the upper valve, and Fig. c the lower valve. 



Species 7. (Mus. Cuming.) 

 Placunanomia macrochisma. Plac. testa ovatd, soli- 



diusculd, radiativi rude pUcato-costatd, costis valde 



irregidaribus, hie illic iumidis ei bifurcatis ; lutescente- 



albd ; per/oralio)ie mawiim. 

 The largely perforated Placunanomia. Shell ovate, 



rather solid, radiately rudely plicately ribbed, ribs 



very irregular, here and there swollen and bifurcated ; 



yellowish-white; perforation very large. 

 Anomia macrochisma, Deshayes, Revue Soc. Cuvierienne, 



1839, Mag. de Zool. 184.1, pi. 34. 

 llab. Onalaska ; Cuming. Kamtschatka ; Deshayes. 



This fine species is distinguished by a broadly-ribbed 

 growth, the ribs being very irregular, swollen here and 

 and there, and bifurcated, and by a very large orifice. 



Species 8. (Fig. 1 a, b, Mus. Cuming.) 

 Placunanomia Harfordi. Plac. testa ovatd vel oblique 

 transversa, concenirice eximie Jimbrialo-sguamatd, 

 squamis muricatis ; pellucido-albd ; perforatione par- 

 viusculd. 

 Harford's Placunanomia. Shell ovate or obliquely 

 transverse, concentrically delicately fimbriately scaled, 

 scales prickly ; trans|}areni-white ; orifice rather small. 

 Hub. Island of Martinique, West Indies. 



The surface of this species is delicately sculptured with 

 concentric lamina;, surmounted with sharply erect scales. 

 Mr. Frederic Harford, an acute conchologist and most as- 

 siduous collector, after whom 1 have the honour to name 

 it, also possesses specimens. 



Species 9. (Mus. Cuming.) 

 Placunakomia patelliformis. Plac. testa suborbicu- 



lari, convexd vel planatd, radiatim liratd el striatd; 



intus virescente ; apice non. marginali. 

 The dish-shaped Placunanomia. Shell nearly orbi- 

 cular, convex or flattened, radiately ridged and 



striated ; interior greenish ; apex removed from the 



margin. 

 Anomia patelliformis, Linnaeus, Syst. Nat. p. 1152. 



Anomia squama, Gmelin. 



Anomia undulata, Gmelin. 



Ostrea striata, Pulteney. 



Anomia striata, Loven. 

 Hab. Northern shores of Europe (at a depth of from five 



to fifty fathoms) ; Forbes and Hanley. 

 This small fragile species, the only one known on our 

 own shores, is but very slightly striated ; whilst the apex 

 is peculiar in being somewhat removed from the margin. 



