PLATE LXXVII. 
Concavum-zone. 
Figs. 1, 2.—Sonninta semisprnata, S. Buckman. 
Fig. 1.—Portion of the side view, showing the spines and reclining ribs of the 
umbilicus. The specimen is nearly wholly septate. Bradford Abbas. My 
Collection. (Page 343.) 
Fig. 2.—Outline of the whorl-section, partly restored, to show the com- 
pression. 
Figs. 3—5.—Sonninia aLrernata, S. Buckman. 
Fig. 3.—Side view of the type-specimen, to show the irregularity of the 
ribbing. The specimen is nearly wholly septate. Bradford Abbas. From my 
father’s Collection. (Page 346.) 
Fig. 4.—Outline of the whorl-section, taken at about one inch from the end of 
the whorl. 
Fig. 5.—The superior lateral lobe. 
Figs. 6—9.—Sonninia, sp. 
Fig. 6.—Side view of an immature specimen, presumably the young of 
Sowninia wregularis, n. sp. For adult see Pl. XCVIII, and for suture-line of 
this specimen see Pl. LXXXVIII, fig. 4. This is a nearly wholly septate 
specimen, and it shows the strong, regular spinous stage changing to the 
irregular (ribs and spines) stage. Bradford Abbas. My Collection. 
Fig. 7.—Front view of the same fossil, showing size of carina and the ventral 
inclination of the ribs. 
Fig. 8.—Side view of a younger example of the same species. Bradford 
Abbas. My Collection. 
Fig. 9.—Front view of this specimen, showing depressed whorls and carinate, 
almost bisulcate periphery. (The carina is not quite strong enough.) 
