| The embryonic stage, consisting of a small ellipsoid protoconch and ammonitella, ends at about 0.6 mm. |
| The dimensions of the protoconch were measured according to the method set out previously. |
| On the dorsal portion of the rostral face, the shell layers extend ventrolaterally from those of the protoconch. |
| It is not uncommon for both Recent and fossil volutes from southern South America to have a protoconch that is corroded to various degrees by cold acidic waters. |
| The latter species has a smooth, valvatiform, dextrally coiled teleoconch and a sinistral, anastrophic protoconch. |
| The protoconch is paucispiral or multispiral, and is smooth except for a few axial riblets near the junction with the teleoconch. |
