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THE AMERICAX A M TUHALIST [Vol. XLI 



investigator will probably be forced to accept this evidence as 

 indicative of community of descent. If we now take the most 

 closely similar type of the L'ocene clavilithoids, which I think all 

 will agree is found in the forms I have classed as (^lavellofusus — 

 but which Cossmann still considers varieties of Clavtliihes pari- 

 siois/^! Ara^er-K^mer {ClavdJn dcjormis of Cos.maim) ^^e find 

 that Its vouug loads us to some Eocene or earlier fusoid ancestor 

 wliu h iiiav or may not have been the ancestor of the modern Fusi, 

 iiK luduio the Fu6us- cohi9 seiies as well. Assuming, for the sake of 

 niaknig tiie argument as favoral>le as ])ossible to M. Cossmami, 

 that Fusus and Clavilitlies had a connnon ancestor, — which, 

 moreover, is probably the case — antl allowing for the moment 

 that my species of Clavellofusns are varieties of Clavilifhes pari- 



the case — if we allow this, where do we land ? In the first })lace, 

 if youthful characters show relationships at all, — and 1 doul)t if 

 in view of all the evidence accumulated along so many and diverse 

 lines, even Cossmann will have the hardihood to deny this — it is 

 evident that all the Eocene clavilithoids are derived from an Eocene 

 or earlier fusoid ancestor, which we will allow \vas a true Fusus 

 and the ancestor of the modern Fusus as well. Nevertheless, 

 it remains true that Cyrfiiliis scrolmus is a (lcri\ at ion of modern 

 Fusus and not of Eocene I'lisns. a [)oiiit csinUli^hcd hev(md fpies- 

 tion bv the character of its v.mu--. 



If (o.MnaiMi UM, to (ont nd du.r both ih, nH<lc.n and die 

 Eo(u.( (laMhtliouU u<,( .IniMd diu<tK tioin a < onunoi, Lo< 'M.e 

 or eaih.i aii(<st,„ thd, would b- .oiii,- uason in hi. u.ttlaiing 

 all tlicsc <liv(M-g.>iit lines into a common generic boundary. Tlie 

 question would then.be boiled down to that of the greater or less 

 elastic it\ oi the generic boundaries But Cossmann holds that 

 Ci/tfulus s,u>lnnis a descendant of (Maxihthcs c|uoiciu'elle 

 [( Mtnhi^l .on !< d.Mdidant iinmMhat d.s ( l.iMiuhe." ahhoiii,di 

 tli( u.niu sta„. . .how that this not tlu < aM a. ( \< n .tud. nt of 

 ])lulo^u.^ ot MolhiMa axlMhK.d tioin .lu 11 >tin<tin. uill h ad.K 



