68 AMMONITID^. 



into a bi'oad, short lobe. The last whorl frequentl}^ differs in 

 form and sculpture from the inner whorls. The lobes are dis- 

 tinguished by their broad saddle stalks, with divisions cut in 

 oblic^uel}', the oblique position of the tips of the lobes, great 

 development of the principal lobes, and striking reduction of 

 auxiliary ones. 



HALORiTES, Mojs., 1879. Body-chamber and spiral of the 

 whorls as in Arcestes. Inner whorls with granulose ribs ; saddles 

 elevated, with many narrow lateral branches ; lateral lobes 

 reduced ; last whorl with a different form and sculpture from the 

 others ; aperture a little contracted ; a wrinkled Isijev present. 



JUVAVITES, Mojs,, 1879. Differs from Halorites by its last 

 whorl resembling the preceding ones, and its less dentate lobes ; 

 the shell bears traces of periodical contractions. 



DiSTicHiTES, Mojs., 1879. Convexity of the shell with a median 

 groove, usuall}' bordered by carinse ; inner whorls having the 

 ornamentation of T. Jockelyi ; last whorl with additional ribs' 

 intermediate to those which ornament the preceding whorls ; 

 body-chamber occupies more than a whorl ; lobes as in Sagenites. 



EuTOMOCERAS, Hyatt, 1877. 



Distr. — E. Laubei^ Meek (xxxvii, 6, 7). Trias ; Nevada. 



Characterized by its lenticular form, narrow umbilicus, appa- 

 rently at all ages very sharp external keel, without furrows or 

 lateral ridges, and small regular arched pilse on middle-sized 

 specimens, growing wider, more irregular, less distinct, and 

 developing small lateral lobes on the adult, with both nodes and 

 pilae becoming obsolete on the larger part of the body-volution. 



Geratitse. 

 Ceratites, de Haan., 1825. 



Syn. — Haaniceras, Bayle, 1878. 



Distr. — Permian, Trias. The Cretaceous forms referred to 

 Ceratites perhaps belong to another group. C. nodosum., Brug. 

 (xxxii, 23). 



Shell discoidal, more or less sculptured ; sutural line with 

 simple, rounded saddles, and shallow denticulated lobes ; anti- 

 siphonal lobe doubly toothed. 



TiROLiTES, Mojs., 1879. Lobes not toothed, or showing the 

 commencement of teeth ; second lateral lobe more or less sal- 

 ient ; convexity of the whorls smooth, rounded, nearly flat. G. 

 Idrianus, Hauer. 



BALATONiTES, Mojs., 1879. Periphery with a tuberculated 

 carina. G. Balatonicus, Mojs. 



HUNGARiTEs, Mojs., 1879. Shell narrow, with a much elevated 

 median carina ; lobes as in Ceratites. G. Zalaensis, Bockh. 



ACROCHORDiCERAS, Hyatt, 1877. This group is closely allied to 



