CEPHALOPODA— ORTHOCHOANITES. 



91 



XXXVII. Phacoceras Hyatt. 

 Strongly involute nautilicones with compressed acute whorls in 

 adult, but young quadragonal as in Discitoceras; impressed zone 



Fig. 131 1. Phacoceras dumblii, X M- (After Hyatt, Texas Survey, II.) 



deep; suture with ventral saddle and broad lateral lobes. Missis- 



sippic-Permic. 



108. P. dumblii Hyatt. (Fig. 13 11.) Carbonic. 



> Fig. 1312. Thrincoceras depressum, X /^- (After Hyatt, Texas Surv. ) 



