BEEKMANTOWN AND CHAZY FORMATIONS OF CHAMPLAIN BASIN 47I 



taining an average depth of 4.5 mm in the ephebic stage. Septa quite 

 concave, their concavity equal to the depth of the cameras ; sutures 

 pass nearly straight transversely, with hardly any trace of a ventral 



Fig-. 27 Tarphyceras clarkei sp. nov. Section of type (pi. 22). Natural 



Fig. 28 Fig. 2q Fig 30 Fig. 31 



Fig. 28-31 Tarphyceras clarkei sp. nov. Transverse sections \ 



Fig. 28 Section through 2d volution ; tig. 29, section at end of 3d vol. ; rig. 30, section at begin- 

 ning of living chamber ; fig. 31, section through middle of living chamber 



saddle in the ephebic and gercntic stages, or even a slight recession 

 of the suture in the early ephebic stage upon the abdomen. 



