Shell Morphology in Cephalopods

longicone
- Long shell which may be curved or straight. image

brevicone
- Short broad shell which may be curved or straight.. image

orthocone
- Short or long straight shell. image

cyrtocone
- Short or long curved shell which completes less than a full volution. image

gyrocone
- Long curved / loosely coiled shell which completes one full volution (360°) or more, but in which the whorls do not touch. image

evolute
- Coiled shell in which the whorls touch but do not overlap; all whorls are exposed in side-view. Also called serpenticone. image

convolute
- Tightly coiled shell in which the last whorl covers much of the preceeding whorls. image

involute
- Tightly coiled shell in which the last whorl covers all of the preceeding whorls. image

nautilocone
- A convolute or involute shell

torticone
- Shell coiled in a three-dimensional spiral, like a snail shell. image