[243]

Diplactura = Stellated shell with double tail; δίπλους, ἀκτίς, ὀυρά.

[244]

Amphiactura = Stellated shell with tail on both sides; ἀμφί, ἀκτίς, ὀυρά.

[245]

Trigonactura = Triangular shell with three rays; τρίγονον, ἀκτίς, ὀυρά.

[246]

Hymenactura = Star-shaped shell with membrane between the rays; ὑμήν, ἀκτίς, ὀυρά.

[247]

Astractura = Star-shaped shell with many rays; ἄστρον, ἀκτίς, ὀυρά.