AMMONITES. 35 



21. Ammonites Cunningtoni, Sharpe. Plate XV, fig. 2. 



A. testa injlatd, tuberculato-spinosd : anfractibus tumidis rotmidatis ; lateraliter 

 biseriatim spinosis ; dorso planulatis, tuberculatis : tuberculis dorsalibus imprimis tri- 

 serialibuSy medio numerosioribus, dei/ide obsoletis ■■ umbilico magno -. aperturd transversim 

 ovali : septoru)/i lobis lateralibus, superiore bifidd, inferiore trifidd. 



Shell with few broad rounded whorls, each with two lateral rows of about ten spinose 

 tubercles, one row of moderate size near the umbilicus, the other of large spines at the edge 

 of the back : three rows of smaller elongated tubercles on the back ; those of the two 

 outer rows corresponding in number to the lateral spines ; in the central row two or three 

 smaller tubercles to each of the others : as the shell increases in size the tubercles of the 

 middle row gradually disappear, and the other dorsal tubercles coalesce with the spines, 

 leaving the back smooth, and only four rows of large spines on the whorl : umbilicus 

 large, leaving nine tenths of the inner whorls visible : aperture transversely oval : superior 

 lateral lobe of the septa bifid, inferior lateral lobe trifid. 



Diameter, 6 inches ; width, 3 5: inches ; height of aperture, 2^ inches. 



The only specimen seen was found in the Grey Chalk of Upton Scudamore, near 

 Warminster. 



This species is nearly related to A. Sussexie?isis, from which it is distinguished by its 

 broader whorls, fewer and larger lateral tubercles, and diS'ereut arrangement of the dorsal 

 tubercles. The species is named after William Cunnington, Esq., F.G.S., of Devizes, 

 whose zeal in illustrating the Geology of his neighbourhood entitle him to our gratitude. 



