lxxxiv 



INFERIOR OOLITE AMMONITES. 



Bed, or associated marl (Mr. D. Stephens) ; Burton Bradstock, in a somewhat 

 iron shot matrix — a bed I have not met with there (Mr. Tutcher). 



Fig. 45. — Brasilina Tutcheri. Stoke Knap. 



Date of Existence. — Bradfordensis hemera, presumably. 

 3. Brasilina ceinalis, 8. Buchnan. Supph, Plate X, figs. 29 — 31. 



Description. — Platyleptogyral, concavumbilicate, striate. 



Distinction. — From B. Tutcheri, decline of ornament. 



Localities and Strata. — Dorset : Halfway House, from a somewhat ironshot 

 matrix ; Sherborne, evidently from the BhynchoneUa ringens bed — an adult specimen 

 140 mm. in diameter, with mouth border ; its test is quite smooth. 



Date of Existence. — Bradfordensis hemera. 



XXXII. Genus — Ludwigella, S. Buchnan. 



(Type : Ludwigella arcitenens, sp. n.) 

 1887. Ludwigia (pars), This Monogr., p. 16. 



1901. Ludwigella, Proc. Cotteswold Club, vol. xiii, p. 266. 



1902. Ludwigella, Emend. Amm, Norn., p. 4. 



Definition. — Platyleptogyral, subangustumbilicate ; subdensiseptate, subbrevi- 

 subangustilobate; laterally anguliradiate; peripherally anguliradiate, subacutifasti- 

 gate, carinate. 



Distinction. — From Brasilina, a more biarcuate radial line, 

 greater compression, coarser character of ornament. 



Note. — The above details apply only to the arcitenens series — 

 \ the Ludungellse verse. The other series, into which the species 



"^ arranged provisionally under Ludwigella are divided, have their 



line of own characters (see below). With better knowledge, to be derived 



arcitenens. from more material, they will doubtless require generic distinction. 



