CEPHALOPODA— ORTHOCHOANITES. 8 1 



sions close-set and short, projecting only about 3 mm., and some- 

 what frilled. Internal mold with low annulations. 

 Onondaga of New York and Ontario. 



91. R. trivolve (Conrad). (Figs. 1297, 1298.) Devonic. 



Fig. 1297. Ryticer as trivolve^ X %• (After Hall.) 



A loose gyroceracone, with the characters of the preceding. 

 Onondaga of New York. 



92. R. matheri (Conrad). (Fig. 1299.) Devonic. 

 Differs from the preceding in its closer coil with the final por- 

 tion less curved, the section elliptical, the septa more distant and 

 the expansions more emphasized in the internal mold by regular, 

 rib-like undulations. 



Onondaga of New York. 



93. R. Cyclops (Hall). (Fig. 1300.) Devonic. 

 Larger and more robust than preceding; coil regular. and rapidly 



expanding ; section broadly oval ; undulating lamellose growth lines 

 and obscure, broad, longitudinal ridges occur. 

 6 



