A. nitida.
A. argo. The Portuguese man-of-war. Pl. [35], fig. 1.
Characterized above; shell whitish, fragile, keel rather narrow, with sharp-pointed tuberculations; sides striated transversely, wrinkled longitudinally.
A. tuberculosa. The tuberculated Argonaut. Pl. [35], fig. 2.
Species more convex at the sides, with nodulous elevations; keel broader, points more obtuse.
2. Carinaria. The glassy Nautilus. Three species.
In form and texture greatly resembling the Argonauta, but distinguished by only having one keel on the whole length of the back.
Shell symmetrical, carinated or not, very thin, slightly compressed, without spire, but with the summit slightly recurved posteriorly; aperture oval and very entire.
Carinaria vitrea.
C. fragilis.