xxxviii INFERIOR OOLITE AMMONITES. 



History. — Figured and described in the body of this work as Ludwigia costosa, 

 identified with Am. opalinns costosus, Quenstedt. But it is distinctly thinner than 

 the preceding species, which is now, with better reason, identified therewith. 



Localities and Strata. — Dorset : Burton Bradstock, with the foregoing. 

 Somerset : Stoford, near Yeovil, in a bluish-grey limestone. 



Date of Existence. — Scissi hemera. 



5. Lioceeas geacile, 8. Buclcman. Suppl., Plate VI, figs. 11 — 13. 



Description. — Platyleptogyral, subconcavumbilicate, flexi-subparvicostate. 

 Distinction. — Less umbilicate than any of the foregoing species. 

 Locality and Stratum. — Burton Bradstock, with the preceding species. 

 Date of Existence. — Scissi hemera. 



B. Species which show a costate followed by a striate stage. 



They are distinguished from any of the foregoing by the costse changing to 

 strise at a fairly early period of growth. 



6. Lioceeas bifidatum, S. Buclcman. Suppl., Plate VII, figs. 1 — 6. 



Description. — Platyleptogyral, gradumbilicate, flexicostate, changing to flexi- 

 striate. 



Bemarlcs. — The costate stage gives place to a striate stage, in which the ribs 

 are only partially developed. Later the ribs appear only as somewhat irregular 

 wave-like bulgings developed in the middle of the lateral area. 



Locality and Stratum. — Burton Bradstock, with the foregoing species. 



Date of Existence. — Scissi hemera. 



7. Lioceras plicatellum, S. Buclcman. Suppl., Plate VIII , figs. 10 — 12 ; 



Suppl., Plate IX, figs. 7—9. 



Description. — Platyleptogyral ; subconcavumbilicate, becoming excentruinbili- 

 cate in adult; flexistriate. 



Remarks. — The costate stage gives place at an early date to a striate stage. 



