MONOGRAPH 



CARBONIFEROUS CEPHALOPODA OF IRELAND. 



Sub-order NAUTILOIDEA. 



Famihj Okthocebatid.'E. 



A. LONGICONES. 



I. Group Lj;via. 

 SuE-GHOUP Ci/Jhidriformes (siphit)icle ci/lindrical). 

 Germs Okthoceuas, Jlreijn, 1732. 

 Orthoceeas Leinsterense, a. H. Foonl. Plate I, figs. 1 (/ — c. 



189G. Oethoceras Leinsteuense, A. H. Foonl. Ueber die Orthoeereu des 



Kohlenkalks (Carboniferous Limestone) 

 von Irland. . . . luaugural-Disserta- 

 tiou zurErlaiigung der Doktorwiirde . 



der Kgl. bayer. Ludvvig-Maximilians- 

 Uuiversitiit zu MUncheu, p. 13. 



Bescriptiun. — Shell somewhat elongate, straight, tapering at the rate of about 

 1:7. Section elliptic, perhaps partly by pressure, the ratio of the greater to 

 the lesser diameter being as 7 : 6. Body-chamber of moderate length, about 

 120 mm., which probably represents not more than oue-foui'th of the entire 

 length of the shell ; the specimen, however, is not perfect enough towards the apex 

 to supply material for accurate measurement. There is a small, well-marked 

 constriction on the cast of the body-chamber, just below the aperture, but this 



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