478 University of Kansas Geological Survey. 



lar, rounded costse, which pass nearly straight across the sides 

 of the whorls, and arch slightly forward in crossing over the 

 periphery on which from thirty-six to forty of them may be 

 counted to every turn ; each of those commencing at the um- 

 bilicus, usually there a little enlarged, especially on the larger 

 whorls, so as to form a small subnodose prominence. Beyond 

 these they all bifurcate regularly once, near the middle of each 

 side, and on the larger turns others are also intercalated between 

 so as to make the number on the peripheral side five or six times 

 as great as at the umbilicus. The septa are rather crowded, 

 and provided with branched and deeply sinuous lobes and 

 branches. The siphonal lobe is about one-fourth longer than 

 wide, nearly obovate in form, and ornamented with three prin- 

 cipal branches on each side, the two terminal of which are 

 larger than the others, and each provided on the outer side 

 with two or three more or less digitate terminal branchlets, 

 while the inner parallel margins are merely sharply serrated. 

 The first lateral sinus is of about the same size as the si- 

 phonal lobe, a little oblique, nearly oblong in form, and di- 

 vided at the extremity into two tripartite and obtusely digitate 

 branches, of which the one on the outer side is larger than 

 the other ; behind these it is provided on each side with two 

 alternating lateral branches with sinuous margins. The first 

 lateral lobe is narrower and shorter than the siphonal lobe, 

 and provided with two principal branches on each side, the 

 two terminal of which are much larger than the others and 

 of unequal size, the one on the right or peripheral side being 

 the larger. Both of these terminal branches are distinctly 

 bipartite, the subdivisions being ornamented with several 

 branchlets and digitations. The second lateral sinus is about 

 half as wide and nearly two-thirds as long as the first, more 

 or less oblique, and rather deeply divided at the extremity 

 into two subequal, bifurcating and obtusely digitate terminal 

 branches. The second lateral lobe is as long as the second 

 lateral sinus, but a little narrower, and ornamented with three 

 variously digitate terminal branches, the middle one of which 

 is longer than the others, a little oblique, and not exactly cen- 



