572 



MOLLUSCA 



SUB-KINGDOM VI 



Scaphites, Park. (Figs. 1189, 1190); Discoscaphites, Meek; Anascaphites, gen. nov. 



Type A. (Scaph.) ventricosus, Meek sp. ; Jahnnites, 

 gen. nov. Type J. (Scaph.) Geinitzi, var. binodosus, 

 Jalm. sp. Cretaceous. 



Family 9. Lytoceratidae. Neumayr (pars). 



Scaphites spiniger, Schliiter. Upper Creta- 

 ceous (Senoniaii) ; Coesfeld, Westphalia. 



FIG. 1100. 



Scaphites aequalis, Sowb. 

 Ceno mania n ; Roue n, 

 France, */! 



I - 



FIG. 1191. 



Lytoceras flnibriatmn, Sowb. 

 sp. Middle Lias; Wiirtembt-ri,'. 

 Cross-section (cf. Fig. 1090). 



Includes only closely coiled, discoidal, and involute shells with somewhat prominent, 



often crenulated transver.-e bands of growth. 



Antisiphonal lobe with two long internal 

 branches bending inwards and attached 

 to surfaces of the septa. Siphonal lobe 

 short like that of Phylloceras, and 

 siphonal saddles narrow. The first 

 lateral saddles small and short, the first 

 lateral lobes much longer than the 

 ventral. Reduction of lobes along the 

 line of involution is such that there are 

 commonly only six to eight in full- 

 grown shells. 



Lytoceras, Suess. (Thysanoceras, 



FIG. 1192. 



Lytocerus Liebigi, Oppel sp. Tithonian ; Strain berg, 

 Moravia. 



FIG. 1193. 

 Alocolytoceras Genminei, d'Orb. 



sp. Upper 

 Salins, Jure 



yuo (jrC/ //Htt/tt/frj u \ji u. 



Lias ; Piuperdu, near 



Hyatt), (Figs. 1191, 1192). Jura and Cretaceous. Alocolytoceras, gen. nov. (Fig. 

 1193). Type A. (Amm.) Germainei, d'Orb. sp. ; Pleurolytoceras, gen. nov. Type P. 

 (Amm.) hircinum, Schloth. sp. Jura. 



