166 MAZATLAN BIVALVES 
measures long. 1°34, lat. 1°82, alt.°36: an elongated valve 
from the hole of a Lithodomus, Jong. 1°52, lat. °6. 
Hab.—W est Coast of Africa on Ostreairidescens, Stutchbury.— 
Mazatlan ; extremely rare, on Chame and Spondyli; L’pool 
Col.—Panama, among pearl oysters; F. Archer. 
Tablet 745 contains a young perfect pair, both valves detach- 
ed, with hole lke Anomia.—746, a broken attached valve, 
shewing the hinge and portions of the plug.—747, the elongated 
valye.—748, the largest pair, detached, nearly perfect. 
217. PLacUNANOMIA FOLIATA, Brod. 
Brod. in Proc. Zool. Soc. 1834, p. 2.—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. 
loe. cit. 
Only two young and transparent valves were found of this 
species. White, with central brown stain; outside with 
prickly longitudinal strie. They seem to agree with a very 
characteristic valve found in the 8. W. Mexican collection. 
Wong. 10," (lat.. OF: 
Hab.—Guayaquil Bay ; on dead Pinna in sandy mud, 11 fm. ; 
Cuming.—Ecuador, Guayaquil, D’ Orbigny.—tIsle 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 
ealcifer ; L’pool Col. 
Tablet 749 contains the larger valve and fragments. 
218. PLACUNANOMIA CLAVICULATA, %, S. 
P. t. suborbiculari, tenuissimd, planatd, levi, seu striis in- 
erementi exillimis: alba, macula brunned discam candidam 
pyriformem haud distinctam circumeunte ; valvd inferiort hya- 
lind, perforatione magna, fulchro VY -formi : lamella albd 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. 
