Tectibranchiata
Tec`ti`bran`chi`a´ta
| n. pl. | 1. | (Zool.) An order, or suborder, of gastropod Mollusca in which the gills are usually situated on one side of the back, and protected by a fold of the mantle. When there is a shell, it is usually thin and delicate and often rudimentary. The aplysias and the bubble shells are examples. |