BRACHYTREMA. 99 



p. 5, pi. 44, fig. 27), approaches our shell still more closely, but the spiral ornamen- 

 tation of Lycett's species is finer, more crowded, and more granulated. It is 

 true that in all these cases the differences are chiefly connected with the ornamen- 

 tation, and in this respect B. subvaricosum certainly differs from all known forms 

 of Brachytrema in the Great Oolite of this country. It is possible that this may 

 be the form described by Cossmann (p. 79, pi. xi, figs. 34 and 35) as Brachytrema 

 brevis, Piette, said to be not uncommon in the Bajocian of the Meurthe-et-Moselle. 

 Brachytrema subvaricosum, occurs sparingly in the upper part of the Lincolnshire 

 Limestone at Great Ponton. There is also a wide-angled variety, with the spirals 

 very wide apart, which has been found at Weldon. 



L8. Beachyteema binodosum, sp. n( 



Description. — This little shell differs from all others of the varicosum-growp in 

 having two nodular spiral belts round the whorls, which give it an eucycloid aspect. 

 A single specimen has been found at Great Ponton. 



19. Beachyteema Weightii, Cotteau, 1855, var. despecta. Plate II, figs. 8 a, b, e. 



I860. Beachttrema Weightii, Cotteau. Heb. and Desl., Foes, de Montreuil- 



Bellay, p. 21, pi. vii, figs. 7 a, b, c. 



Description : 



Length . . . . . 7"5 mm. 



Width . . . . .6 mm. 



Body-whorl to entire shell, about . . 55 : 100 



Spiral angle . . . .65° 



Shell conical ; apex pointed. Whorls five, angular, and step-like ; ornaments 

 coarse ; three strong nodulated spirals on the anterior area of each whorl ; the 

 longitudinals consist of tolerably numerous stout costas which are very nodular 

 over the angle of the whorl ; base rather flattened and ornamented by five spiral 

 lines. 



Aperture subquadrate to circular; notch rather wide ; scarcely any canal. 

 Relations and Distribution. — Owing to the indifferent preservation of the 

 anterior margin of the only known specimen it is not easy fully to point out how 

 the form now under consideration differs from Cotteau's species. It is not much 



