188 



m;\\ V(»kk siai'k mcskcm 



In many cases it ai>poars as if the siplnnunlar tube may have 

 Ihmmi absorbed or olhci-wisc rciiioNcd bcl'oic Ihc lillinu,' of the 

 cavity b('«;an.^ 



AiiKniii- llie more abinidnnt sj)ecies are: 



()i ili(>c( i-as jM'lojts f li«:-. IDS], a hnm' i-obiist species 

 with nearly or (piiic cciilral sijilmiiclc and stronjily convex septa; 



Fig. 112 Orthoccras thoas 



Fig. 113 C >■ r t o c c r a s e u y e ii i u iii 



() . ( A c t i n o ce r a s?i 1 u x u m [tii>-. 101)], the most abundant 

 species, cliaracterized by moderately tapering form, close-set 

 septa and expansion of si])lnin(de between the septa, as well as 

 inlerseplal organic dejjosits; O . s t y I n s [fig. 110], easily reeog- 



'Ilnll. .T.Miiics. I'jiliU'ontolo^'y of Now York. v. 5. pt2, p.228. 



