SECOND SECTION OF THE SUB-FAMILY OF BALANINÆ.
Reading edition
SECOND SECTION OF THE SUB-FAMILY OF BALANINÆ.
[Scutum and tergum (when both are present) not overlapping each other, or articulated together; basis membranous; parietes often deeply folded, with the outer lamina, towards the basis, generally imperfect; each branchia composed of two plicated folds; shell attached to living vertebrata.]