400 INFERIOR OOLITE AMMONITES. 



y. Inner lateral lobule in duplicate. 



Pig. 36. — Outline of L of Sonn. crassibullata. 



SONNINIA CRASSIBULLATA. Plate CIII, fig. 17. 



See Plate LXXX, figs. 1—3, and page 353. 



It is probable that the suture-line of the type is abnormal, so far as regards 

 the duplication of the inner lateral lobule of L. If the upper of the two lateral 

 lobules were absent, and if there were a corresponding increase in the size of the 

 lower one, the septation would be in agreement with that of the foregoing series. 



In the suture-line shown in PI. LXXX, fig. 3, there is a general agreement 

 with those of the foregoing species ; but here, again, there is a feature presumably 

 abnormal for these Sonninise, namely, an ultra-axial position of the terminal lobule 

 of L. 



Sonninia injEQUA, 8. Buekman. Plate CI, figs. 4 — 6. 



Discoidal, compressed, carinate. Whorls ornamented with inconspicuous, 

 subundulate, slightly subsigmoid, reclinate * costse, inclined but obscure ventrally. 

 Ventral area arched, divided by a small, rounded, doubtfully hollow carina, less con- 

 spicuous with age. Inner margin sloped, subconvex, fairly defined. Inclusion one- 

 half. Umbilicus graduate, slightly excentric, ornamented with small costse closely 

 set in the central whorls, apparently destitute of spines. 2 Whorl-section oblong. 

 Septa somewhat ornate, the superior lateral lobe asymmetrical, the lateral lobules 

 anisometric, the outer lobule larger than the inner, incipiently tripartite ; the 

 terminal lobule intra-axial, very anisosceloid, and very inequicellate ; the inner 

 lobule small ; and beyond the inner lobule an extra lobule is projected from the 

 main stem of the lobe. 



1 More upright with age. 



2 Up to about 8 mm. of umbilical diameter the whorls are badly preserved. 



