Io8 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



ciful relationships to his genera of Triassic ammonites. 

 The only systematic attempt to group all goniatites into 

 genera and families is Hyatt's classification, "Genera of 

 Fossil! Cephalopods,"^ where all known species were 

 grouped into genera, and these in turn in five families: 

 Nautilinida, Lower and Middle Devonian; Priniordialidce, 

 Upper Devonian; Magnosellaridce, Middle and Upper Dev- 

 onian; GlyphioceratidcB, Upper Devonian, Carboniferous, 

 and Permian; ProlecanitidcB, Upper Devonian, Carbonif- 

 erous, Permian, and Trias. 



Steinmann^ groups the goniatites into two families sup- 

 posed to be derived from the two chief genera of the Nautil- 

 inidcB, Anarcestes, and Mimoceras. On page 399 of his 

 work is given a table showing the supposed genetic connec- 

 tion of the various genera and also their relationship to their 

 ammonite successors of the Mesozoic. These relations'hips, 

 however, are purely speculative, and not based on ontoge- 

 netic study of the groups. 



Zittel in his later work^ recognizes only two families, 

 GoiiiatitidcB and ProlecanitidcB, of which the former com- 

 prises the JVantilinidce, Primordialidce, Magnosellaridce , 

 and Glyfhiocet'atidcB. These subdivisions may then be re- 

 tained with the rank of subfamilies. 



GLYPHIOCERATIDyE Hyatt. 



This group was established by Hyatt^ to include a num- 

 ber of species from the Upper Devonian, Carboniferous, 

 and Permian. The oldest genera are Brancoceras and 

 Prionoceras, which began in the Upper Devonian, attained 

 their acme in the Lower Carboniferous, and lived on into 

 the Coal Measures. Both genera are smooth-shelled, and 

 both have a pointed, undivided, ventral lobe, and two pairs 

 of lateral lobes, of which the first is angular; the saddles 

 of most species of both genera are broadly rounded, 



iProc. Boston Soc. Nat. Hist., 1883, Vol. XXII. 

 - Elctnente der Palseontologie, 1890. 

 ^Grundzuege der Palaeontologie, 1895. 

 *Proc. Boston Soc. Nat. Hist., Vol. XXII, p. 322. 



