CEPHALOPODA— AMMONOIDEA. 1 5 1 



and rounded sides ; surface with constrictions or varices only ; septa 

 goniatitic, the external lobe divided by a siphonal notch, a lateral, 

 and an auxiliary, all rounded ; antisiphonal lobe undivided, flanked 

 by two pairs of laterals. Triassic. 



237. N. dieneri Hyatt and Smith. (Fig. 1401, a-c.) Triassic. 

 Small ; whorls slightly wider than high, each indented more than 



half the height of the preceding whorl; surface with numerous 

 (10 or more) varices and constrictions. 

 Lower Triassic Meekoceras beds of Inyo Range, California. 



XCVII. Paranannites Hyatt and Smith. 

 Like Nannites but with ceratitic sutures. Triassic. 



238. P. aspenensis Hyatt and Smith. (Fig. 1401,^/-/.) Triassic. 

 Highly arched whorls with flattened sides and rather broadly 



v/ A 







P'iG. 1401. a- c, Nannites dieneri, X /^> and suture enlarged ; d-f, Paranannites 

 aspenensis, two views X %> ^^^ suture enlarged ; g-i, Aspenites acutus, X /^> ^"^^ 

 suture enlarged, (After Hyatt and Smith.) 



rounded venter ; umbilicus narrow ; height of whorls half diameter 

 of shell ; surface with very weak folds and occasional constrictions ; 

 saddles rounded, lobes sharply notched. (Type of genus.) 

 Lower Triassic Meekoceras beds of Idaho. 



PiNACOCERATIDA. 



XCVIII. Aspenites Hyatt and Smith. 



Compressed, involute, deeply embracing, discoidal shells, with 

 flattened sides; acute venter surmounted by a keel and closed um- 



