CEPHALOPODA— CYRTOCHOANITES. 



131 



187. H. cacabiforme Newell. Siluric. 

 Of medium size, straight; transverse section subcircular; living 



chamber short, less than three fourths greatest diameter; septal 

 edges crenulated; lateral lobes of aperture strong, elevated, more 

 regularly curved and more distinct than in H. herzeri; hyponomic 

 sinus longer, more slender, widening at the margin. 

 Niagaran of northern Indiana. 



LXX. Septameroceras Hyatt. 

 Like the preceding but with addition of a median sinus. Siluric. 



188. S. septoris (Hall). (Fig. 1379.) Siluric. 



Fig. 1379. Septameroceras septoris, side and apertural view of living chamber. 

 (After Hall, 20th Mus. Rep.) 



Aperture gradually contracting; apertural view ovate; brachial 

 and median sinuses all distinct, rounded at the ends. 

 Niagaran of Wisconsin. 



LXXI. Phragmoceras Sowerby. 

 Laterally compressed, endogastric cyrtoceracones and gyrocera- 

 cones, of oval section with narrowly rounded venter; siphuncle 



Wli\ 



Fig. 1380. Phragmoceras nestor, 

 apertural view. (After Hall, 20th 

 Rep. N. Y. State Mus. ) 



Fig. 1 38 1, Phragmoceras nestor, X Yi- 

 (After Hall, 20th Rep. N. Y. State Mus.) 



