CEPHALOPODA— AMMONOIDEA. 



137 



Fig. 1389. a, b, Manticoceras intuviescetis (fl' X Vi) \ ^^ Probeloceras hdheri^ X 

 ^ ; d, Tornoceras uniangulare, y^ '%', e, suture of same. (After Hall.) 



203. M. sororium Clarke. (Fig. 1390, c.) Devonic. 



Small ; young broader, adult narrower than preceding ; sides flat ; 



Fig. 1390. a, Manticoceras intumescens, section ; b, d, M. rhynchostovia, X % \ 

 Cy M. sororium, section, X Y^- (After Clarke.) 



young ornamented by varices, which become obsolete in adult. 

 Naples shales of New York. 



