GASTEROPODA. 365 
A remarkably elevated species, and conspicuous for its dark, radiate 
exterior. Sometimes there are also concentric bands of lighter colour. 
In some specimens the aperture is nearly circular, in others elongated- 
ovate. In shape and colour it agrees with F’. Caffra, Chemnitz, from 
the Cape of Good Hope, and also with F. afra, Quoy, from the Cape 
de Verde Islands. 
Figures 473, 473 a, 473 0, three views of the shell. 
FIssURELLA CRuCIATA (Gould). 
Testa parvula, tenuis, nitida, elongato-ovata, arcuatim elevata, costulis 
radiantibus eminentibus ad triginta cum filis confertis, ordinatis 
concentricis decussata ; apice antertori, fissura elongata ; coloribus ni- 
gris et albis cruciatim signata: intus nitida, livido et albo picta ; mar- 
gine crenulato. 
Fissurella cruciata, Goutp; Proceed. Boston Soc. Nat. Hist., i. 
156. August 1846. 
SHELL minute, thin, shining, elongated-ovate, somewhat arched, 
rounded at extremities, apex elevated at the anterior third, with a key- 
hole perforation slightly contracted at the sides. Surface sculptured 
with about thirty elevated, rounded, radiating ribs, for the most part 
alternately larger and smaller. These are crossed by concentric series 
of regularly and closely arranged elevated threads, which are slightly 
imbricated, giving the surface a beautifully cancellated appearance. 
Colours black and white, arranged so that radiating patches of black 
correspond to the two diameters, and of white to the two diagonals, 
the latter not continued to the margin. Edge very finely crenulated. 
Interior white and shining, but blue at the parts which correspond to 
the black of the exterior. A thick callus fortifies the perforation. 
Length two-fifths of an inch; breadth one-fourth of an inch ; height 
one-eighth of an inch. 
Inhabits the Sooloo Sea. 
This very closely resembles F’. minuta, Sowerby (Conch. IIl. f. 16), 
92 
