ACEPHALA. 443 
Inhabits New Zealand. 
Outline much as in A. fucata, but the caudal region is much more 
compressed. Its smooth surface and widely different coloration are 
easily recognised. The white radiations are opaque, and have a super- 
ficial appearance. 
Figures 552, 552 a, outer and inner surfaces of the shell; 552 8, dor- 
sal view. 
AvicuLa pica (Gould). 
Testa solidula, ventricosa, per-unequilateralis, oblique rotundata, ecau- 
data; margine caudali parum producto ; extus calcarea, nigro radiata: 
auricula triangularis, crenulata ; fissura profunda : margarita pallide 
aurea; limbo calcareo lato, vitreo, albo et nigro radiato: margo car- 
dinalis latus, incrassatus ; dente cardinali papilliformi ; dente laterah 
brevi, antice incrassato et deflecto, in valvd sinistra bifurcato ; cicatrice 
musculart reniformi, profundo. 
Avicula maculata, Goutp ; Proceed. Boston Soc. Nat. Hist., 111. 309. 
Dec. 1850. Expedition Shells, 90. 
SHELL small, solid, height and length about equal, a little oblique, 
broadly rounded; surface chalky white radiate with dusky purple ; 
rather convex, left valve most so; superior margin short, thick; pos- 
terior dorsal edge compressed, not produced ; posterior margin a little 
sinuate; surface finely laminated, not produced into scales; auricle 
rather large triangular, as broad as long; margin conspicuously crenu- 
lated; byssal notch deep; nacre pale golden-yellow; shelly margin 
broad, variegated blue-black and porcelain-white ; a minute cardinal 
tubercle; hinge margin broad and thick, with a short lateral tooth, 
enlarged and curved downwards at the end; bifurcated in the left 
valve; a conspicuous range of muscular dots traversing down from the 
beaks; byssal tuberosity of left valve broad triangular. 
Length and height an inch and three-fourths ; width five-eighths of 
an inch. 
Inhabits Tutuilla, Samoa Islands. 
