PLATE LXXXI. 
Concavum-zone. 
Figs. 1—4.—Sonninta orassinupa, S. Buckman. 
Fig. 1.—Portion of the side-view of the thick, umbilicate form. Bradford 
Abbas. (Page 351.) 
Fig. 2.—Outline of the whorl-section, with test. 
Fig. 3.—Portion of the side-view of the thinner, less umbilicate form. Brad- 
ford Abbas. (Page 351.) 
Fig. 4.—Outline of the whorl-section, with test. (Both these fossils are 
immature. They were in the Collection of Mr. Darell Stephens, F.G.S. Now 
in my cabinet.) 
Figs. 5, 6.—Sonninia piversa, S. Buckman, var. 
Fig. 5.—Portion of the side-view. Bradford Abbas. My Collection. (For 
the type-form see Pl. LXXXIII, figs. 1, 2.) (Page 355.) 
Fig. 6.—Outline of the whorl-section, with test. 
Figs. 7—9.—Sonninia spinosa, S. Buckinan. 
Fig. 7.—Side view showing the persistent irregular spinous stage. The 
specimen possesses the greater part of the test. (The last spinicosta is too 
arcuate in the drawing.) Bradford Abbas. My Collection. (Page 365.) 
Fig. 8.—Outline of the whorl-section without test, but the embraced whorl 
with test. 
Fig. 9.—The suture-line of the same fossil, showing cruciform superior lateral 
lobe. 
(For an idea of the younger stages of this species compare Pl. LXXVII, 
figs. 6—9. The young shell, figs. 8 and 9, is almost indistinguishable, but is 
slightly more spinous; the older shell, figs. 6, 7, is, however, more spinous, more 
costate, and more carinate.) 
