- Fig. 1 a, Tetraclita purpurascens, var. with surface disintegrated, and with the sutures united and obliterated.
- 1 b, Tetraclita purpurascens, var. well preserved, with the radii developed; 1 c and 1 d, var. scutum and tergum, internal views.
- 2 a, Tetraclita costata; 2 b and 2 c, scutum and tergum.
- 3 a, Tetraclita vitiata; 3 b, basal edge of portion of wall; 3 c and 3 d, scutum and tergum, internal views of; 3 e, tergum, internal view, var.
- 4 a, Tetraclita cœrulescens; 4 b, scutum and tergum united, external view; 4 c and 4 d, scutum and tergum, internal views.
- 5 a, Tetraclita radiata; 5 b, scutum and tergum united, external view; 5 c and 5 d, scutum and tergum, internal views.
- 6 a, Elminius Kingii; 6 b and 6 c, scutum and tergum, internal views of; 6 d, tergum, var. external view of; 6 e, tergum, another var. internal view of.