FOURTH, OR « ORONK ll: \N BR w< II 171 



The shell of \ ety A ia smooth for three >>r three and a half volutions; tlir 

 tubei spread entirely aero-- the Bides on the firsl quarter of the 



fifth whorl, and about this time the genicuhe have become prominent The chan- 

 nels are m>t present in an) of these specimens, but more <>i less faintly marked 



narrow depressed tones ma) 1 bserved on either — i» 1 « - <>!' the keel. This variety 



lirectl) in'" tli>- next, in which the depressed zones l» come channels. The 

 ilaa differ in aspect from those of variet) A because the) abut against the 

 well defined lateral ridges of the channels. 



developed at about the same period as in variet) A. 

 but the channels appear in t li« - young, ami on the Becond quarter ol the fifth 

 •i>m they an- quite distinct. 



There i« one specimen of variety A in which tin- pike air Blightly inclined 

 . and iln- _r • • n i . • 1 1 1 ; » ■ more prominent than in any other specimen. A 



slight sinking <>t' tin' abdomen in this speci n would produce a form ol 



which is found at Robin flood's Bay in England, and which ha- a 



I, channelled, and flattened abdomen. The single suture which was exposed 



in this specimen possessed remarkably pointed and serrated superior and inferior 



i saddles, and very broad, rounded, but serrated superior lateral lobes The 



auxiliary saddles and lobes were pointed and serrated. There was a ver) large 



siphona] saddle, and all of tin- larger lobes and Baddies appeared of about the 



depth and length. 



One specimen of this Bpecies from Balingen was received in exchange from 



thi' Museum <>i Stuttgardt, under tin- name of Nodotianus. Two specimens in 



Quenstedt's collection belonged undoubtedly to this species, variety A. One 



i Pforen, named l S T o ; 128 . and one from Goppingen 



(No. 11182), were in the Arietenkalk. Tin' last was 63 mm. in diameter and 



a typical form of variety A: tin- pitas are, however, inclined posteriorly, while in 



her they are pointed forwards. In the specimen from Pforen the pilaa begin 



tly near the abdominal side unprt led by tubercles. Other specimens, 



illy the original "t' hi- figure, I'll 1 ' \ II Fig. 6, also from Pforen, show 

 that // ind this species have intermediate varieties. 



era! forms are found in the Semur collection under the name of // 

 R which has smo< _'. with line pilations ami an adult 



whorl havii • this species and also to Arn . var, 



Third Si bsi rii a 

 Amioceras kridioidos, Hyatt. 



ri.i. n i i.. - »,■„.... ii \n i i k -. w. 



Thii tliia 



n( at first ■ ihit species 'Iln- shell i-. how< 



