412 INFERIOR OOLITE AMMONITES. 



Sonninia palmata, 8. Buchman. See Plate XC, figs. 7 — 9, p. 372. 



This species has already been fully discussed. The features of its extra- 

 ordinary superior lateral lobe are approached nearest by those of the two species 

 last described. In the present case, however, there is far greater exaggeration of 

 the outer lobule, so that L is almost bifid. In external ornament the form has but 

 little likeness to the last two : the ribs are distant, somewhat irregular, and 

 reclined. 



C. The lobes are long, though lobes or lobules may degenerate in phyletic 

 development. 



A. The lobes remain long, and asymmetry of L is not pronounced, 



a. Lateral lobules fairly developed. 



Fig. 42. — Outline of L of Sonn. subdecorata. Fig. 43. — Outline of L of Sonn. magnispinata. 



1. Ribs reclinate. 

 * Spines small. 



Sonninia subspinosa, 8. Buchnan. See Plate XLIX, figs. 8, 9 ; Plate LXXXIV, 



figs. 4 — 6, and page 358. 



Sonninia decorata, 8. Buchman: See Plate LXXXIV, figs. 7, 8, and page 360. 



The septal outline is still unknown. The species is placed here from its 

 likeness in other features. 



Sonninia subdecorata, 8. Buchnan. See Plate LXXXIV, figs. 9 — 11, and page 361. 



Sonninia decora, 8. Buchnan. See Plate LXXXIV, figs. 12 — 14, and page 361. 



These last four species were described as the subdecorata -stock (p. 357). Their 

 length of lobe almost suggests that they ought to be placed further on in this 

 series. 



