| 11. | The shell is gibbous adorally, such that the body chamber is widest well behind the aperture.
|
| 12. | It begins as a barrel shaped cadicone, with an eccentric, more or less smooth body chamber.
|
| 13. | Secondary ribs become thicker on the body chambers of microconchs but thinner of body chambers of macroconchs.
|
| 14. | Shells enlarge moderately to the middle of the mature body chamber, then contract gently toward the aperture.
|
| 15. | Secondary ribs become thicker on the body chambers of microconchs but thinner of body chambers of macroconchs.
|
| 16. | They have developed shorter body chambers than in the ancestral Arietitidae, resulting in more stable floating positions.
|
| 17. | The venter, especially of the chambered phragmocone is convex in profile; the body chamber long and tubular.
|
| 18. | Large forms have simple apertures and smooth body chambers while small forms have lappets and ribbed body chambers.
|
| 19. | Large forms have simple apertures and smooth body chambers while small forms have lappets and ribbed body chambers.
|
| 20. | The adult body chamber may equal or exceed the length of the chambered part of the orthoconic section.
|
