Fig. 234. Goniatites complanatus • 

 lutheri (?) —(after Hall). 



290 



complanata. ) No sutures were 

 shown in the original speci- 

 men, which was lost. Sub- 

 sequently the species was re- 

 described in Vol. V. of the 

 Palaeontology of N. Y., and a 

 number of specimens, which 

 Clarke has since shown to 

 belong to different species, 

 were referred to it. The gen- 

 eral characteristics of these 

 specimens were discoidal form, 

 wide umbilication and fine 

 concentric surface striation, features characteristic, accord- 

 ing to Clarke, of the exterior of at least three well-defined 

 species in these shales. The specimen from the "Portage 

 Group, Eighteen Mile Creek, Lake Erie Shore, N. Y.," figured 

 on PI. LXX., Fig. 10, Vol. V., Pal. N. Y., and here repro- 

 duced, probably represents a G. lutheri. 



Goniatites (Manticoceras*) intumescexs. Beyrich. 

 (Figs. 235, 236.) G. patersoni. Hall. (Pal. N. Y., Vol. V., 

 Pt. II., p. 464, Pis. LXXIL, LXXIV. Clarke : Naples Fauna, 

 p. 42.) 



Distinguishing Characters. — About four volutions, the 

 outer embracing the inner to one-half or more of their dorso- 

 ventral diameter; moderately large umbilicus, exposing all 

 the inner volutions; suture forming a narrow acute lobe 

 near the inner margin, then a broad, oblique semi-elliptical 

 saddle, a second narrow, elongate acute lobe, near the outer 

 margin, and a narrow obtuse saddle on the periphery, with 

 one side extremely elongate, and the other very short, forming 



* Manticoceras, Hyatt, "includes species with compressed and often very involute 

 whorls, which are, however, directly traceable by the closest gradations into forms with 

 broad whorls, open umbilici, and an aspect similar to that of Anarcestes. The young are 

 invariably less discoidal than in Gephyroceras, the abdomens rounded, and the sides 

 divergent outwardly. * * The adult sutures have the same general aspect as those of 

 Gephyroceras, but the septa in the compressed involute forms become more decidedly con- 

 vex. The lobes remain rounded until later stages of the growth, the funnel lobes are gen- 

 erally smaller, the larger lateral saddles are also more persistent and retain their forms 

 unchanged even in the extreme old age of the largest specimens.'' (Genera of Fossil 

 Cephalopods, p. 3l~.) 



