166 MAZATLAN BIVALVES 



measures long. 1*34, lot. 1*82, alt. *36: an elongated valve 

 from the hole of a Lithodomus, fr ng. 1*52, Za. '6, 

 J?a&, West Coast of Africa on Ostrea iridescens, Stutchbury. 

 Mazatlan ; extremely rare, on Chamse and Spondyli ; L'pool 

 Col. Panama, among pearl oysters ; F. Archer. 

 Tablet 745 contains a young perfect pair, both v alves detach- 

 ed, with hole like Anomia. 746, a broken attached valve, 

 shewing the hinge and portions of the plug. 747, the elongated 

 valve. 748, the largest pair, detached, nearly perfect. 



217. PLACUNAUOMIA FOLIATA, Brod. 



Brod. in Proc. Zool. Soc. 1834, p. Z.Gray in Proc. Zool. Soc. 

 1849, p. 121 : B. M. Cat. Anom. p. 10. B. M. Cat. D'Orb. 

 Moll. p. 88, no. 778. 



+ P. echinata, Brod. loc. cit., teste Gray. 



+ "P. pectinata, Brod." in Mus. Cuming, teste Gray. 



Subgenus Pododesmus, Phil., Gray in B. M. Cat. Anom. 

 loc. cit. 

 Only two young and transparent valves were found of this 



species. White, with central brown stain ; outside with 



prickly longitudinal strise. They seem to agree with a very 



characteristic valve found in the S. W. Mexican collection. 



Long. "75, lat. '57. 



Hab. Guayaquil Bay ; on dead Pinna in sandy mud, 11 fm. ; 

 Cuming. Ecuador, Guayaquil, D'Orbigny. Isle of Muerte, 

 Broderip. Martinique, no. 6, and Brazils, no. 7 ; Mus. Cum- 

 ing. St. Vincent and Jamaica, Rev. L. Guilding in B. M. 

 S. W. Mexico P. P. C. Mazatlan ; 2 valves in Spondylus 

 calcifer ; L'pool Col. 

 Tablet 749 contains the larger valve and fragments. 



218. PLACUNANOMIA CLAVICULATA, n, s. 



P. t. suborbiculari, tenuissimd, planatd, [l&vi, sen striis in- 

 crementi exillimis : alba, macula brunned disc am candidam 

 pyriformem Jiaud distinctam circumeunte ; valvd inferiori hya- 

 lind, perforatione magnd, fulcliro V -for mi : lamella alba acuta 

 prope perforationem intus decurrente : valvd superiore muse, 

 cicatr. majore subovali, minore rotundatd, modice separata. 

 Subgenus Monia, Gray, loc. cit. 

 Anomia, sp. 2, P. P. C., Cat. Prov. 



