440 MOLLUSCA. 
lossy ; a large callous rib answering to the fissure. Impressions very 
shallow. 
Length an inch and a quarter; height three-fourths of an inch; 
breadth three-tenths of an inch. 
Inhabits the Feejee Islands. 
In the early stages the colour is grass-green, then passing through 
dark purple to coal black. It is remarkable for the perfect flatness of 
one valve. Its destitution of hinge teeth brings it in Lamarck’s genus 
Meleagrina. 
Figures 553, 553 a, exterior and interior of the shell. 
AVICULA LURIDA (Gould). 
T. squamosa, vix obliqua, feré ecaudata, solidula, coloribus rosacets, vt- 
ridibus et flavidis radiatim fucata: valva dextra posticé viz sinuata, 
conveza,; auricula lata, triangularis ; fissura byssica haud profunda: 
valva sinistra ventricosa, tuberculo magno subcaudali munita, postice 
integra: margarita argentea ; limbo cortical: corneo et nigro marmo- 
rato. 
Avicula lurida, Goutp; Proceed. Boston Soc. Nat. Hist., i. 310. 
Nov. 1850. Expedition Shells, 91. 
SHELL small, thin, pendulous, moderately oblique backwards, rather 
higher than long; surface rather loosely laminated; with series of 
close-pressed lanceolate scales near margin; reddish horn colour, 
grass-greenish on disk, with undulating pale radiations becoming 
inclined to dusky in old shells; valves rather convex, left one most 
so; highest part far behind the beaks; posterior dorsal edge compressed ; 
posterior margin broadly emarginate near summit; basal edge circu- 
larly rounded ; dorsal edge oblique forwards; auricle of right valve 
rather large, higher than broad, moderately striated ; notch very small, 
and shallow triangular; nacre light steel-blue, with violet reflections 
projecting, cortical substance broadly radiately marbled with sallow 
white and coal black. Fold answering to byssus-notch very decided, 
