AMMONITES Plicomphalus. 

 TAB. CCCLIX. 



Spec. Char. Discoid, umbilicate; nmhilicus 

 large, with 8 or 10 diverging, rather sharp, 

 protuberances around it ; front rounded, 

 plain. 



Aperture ovate ; about 3-7ths the diameter of the last 

 whorl long ; narrowest towards the front ; the emi- 

 nences about the inner edges of the volutions are wide, 

 and extend over a part of the sides : the umbilicus is 

 large, equalling half the length of the mouth. 



Presented to me by Mr. Weir, who found it in a 

 very mutilated state in the harder part of the Sand- 

 stone stratum, at Bolingbroke, Lincolnshire. 



