﻿94 MB. S. S. BUCKMAN ON CEBTAIN JTJEASSIC [Feb. I9TO, 



Bbadfokdia LIOMPHALA, sp. nov. (PI. X, figs. 4 & 5.) 

 '•Description. — Whorls much compressed, especially around 

 the umbilicus, which is smooth and gradate with au ill-defined rim. 

 Ornament not strong : costaB on outer two-thirds of whorl, inner 

 third almost smooth. 



Remarks. — This species has lain in my cabinet for some twenty 

 years, with the trivial name liomphala attached. It first attracted 

 attention on account of its remarkable likeness to some of the 

 concavumbilicate, or rather subconcavumbilicate Ammonites — ■ 

 species of the type of Ludwigella concava (Sow.), Graphoceras 

 v-scriptum, S. Buckm., etc., which were all once known as Ammo- 

 nites concavus, Sowerby. These are all keeled species of the family 

 Hildoceratidae ; but when this species lay in the rock with its keel- 

 less periphery hidden, it was doubtless often passed over as ' only 

 a common A. concavus.' This perhaps accounts partly for its 

 rarity ; bub when the keelless condition was noted, and search was 

 made for the species, no more than some twenty specimens were 

 the reward of much collecting, though the concxvus-like ammonites 

 were obtainable by hundreds. 



To Plaiy graphoceras apertum, S. Buckm., Graphoceras Umitatum, 

 S. Buckm., and especially to Pseudographoceras compression, this 

 species bears very great resemblance. In fact, in relation to the 

 latter it is almost a case of isochronous homceomorphy. The dis- 

 tinction in all those species is a keel and a costate umbilicus. 



From Oppelia subplicatella, Vacek, 1 pi. xi, figs. 2 & 3 (which seem 

 not to be the same species as bis pi. xi, fig. 1), the different direc- 

 tion of the ribs is sufficient distinction. With 0. subplicatella 

 (fig. 1) the different size of umbilicus and the different thickness of 

 whorls prevent any comparison. 



Locality and stratum. — Bradford Abbas (Dorset), from the 

 Fossil Bed : and certainly by matrix from the upper part ; Stoford 

 (Somerset), from a similar bed. 



D a t e . — Discitce hemera. 



Bkadfobdia costata, sp. nov. (PI. X, fig. G & PI. XI, fig. 1.) 



Description. — Whorls comparatively stout (for a species of 

 this genus) ; ribs somewhat coarse ; umbilical rim small, but 

 distinct. 



Distinction. — From Bradforclia liomphala, stouter whorls and 

 coarser ornament. 



Locality and stratum. — Bradford Abbas (Dorset), in the 

 upper part of the Fossil Bed. Zone of Hyperlioceras discitcs 

 (Bajocian). 



Bradfobdia inclusa, sp. nov. (PI. IX, figs. 2 & 3.) 



Description. — Compressed, much included; umbilicus small; 

 depression on the inner area of the whorl distinct, making the 

 umbilical rim distinct. 



1 ' TJeber die Fauna der Oolithe von Cap San Vigilio ' Abhandl. k.k. Geol. 

 Reicksanst, vol. xii (1886) p. 82. 



