48 FAUNA OF THE OORNBRASH. 



more than one feature, there are others in which the finer details have not been 

 observed, but have been classed only as (1) typicus and (2) macrocephalus. Of these 

 the following is the list : 



(1) From Scarborough (8), Bedford (8), Thrapston (17), Stilton (5), Fairford (6), 

 Sudbrook (3), Edenham (2), Cirencester (1), and Holwell (2). 



(2) From Scarborough (33), Peterborough (4), Thrapston (7), Bedford (1), 

 Holywell (1), and Radipole (1). 



Genus CADOCERAS, Fischer. 



1882. Manuel de Concliyliologie, p. 394. 



" Shell very inflated, umbilicus narrow, keeled, last whorl entirely smooth. 

 The preceding whorls with the ribs forming an angle directed forwards on the 

 ventral region. Ex. (J. viodiolare." 



Cadoceras breve, sp. nov. Plate V, fig. 1. 



Cf. 1886. Ammonites subltevis, Quenstedt, Am. Schwab. Jura, p. 671, pi. lxxix, fig. 3. 



Type. — The numerical characters are as follows : Diameter, 81 mm. ; ratio of 

 transverse diameter, '88 ; last whorl, "37 ; thickness, "41. The centre is occupied by 

 a deep umbilicus, though shallow (breve) for a Cadoceras. Its sides face inwards 

 at a high angle, but are concave and smooth. The diameter, from edge to edge, 

 including some part of the outer chamber, is a third of the whole. The shape 

 of the outer whorl is semi-elliptical, axes as by above dimensions 37 : 20|. The 

 umbilical edge rises on the upper and more distal side by a number of oblique 

 folds, about ten in number in half a whorl ; these become feebler in the body 

 chamber and slant forwards. Further on they give place each to about three 

 weaker, almost evanescent, folds, which still slant forwards and pass over the 

 periphery unchanged, but all die away towards the aperture. About seven 

 eighths of the whorl is body chamber, which shows no further change near the 

 aperture. The septal chambers are distinguished by their crystal interior, but 

 the terminal sutures do not show their outline. The oblique evanescent ornaments 

 and the shallow umbilicus for a Cadoceras are regarded as characteristic, but it is 

 difficult to imagine how the inner whorl can be contained in the thickness of no 

 more than 16 mm. between the visible bases of the last umbilical walls on the two 

 sides (although the fossil has been distorted). The specimen is in my collection, 



